# Structural color ## expand\_more To make a material that is colored, one normally uses a dye or pigment. But another way to make color is to make a nanostructure that reflects or scatters light so that waves of certain frequencies can constructively interfere. These nanostructured materials are said to have s*tructural color.* Unlike traditional color, which comes from dyes or pigments that absorb light, structural color can be made resistant to fading. We use colloidal self-assembly to make nanostructures that have a variety of different colors. At the same time, we aim to understand the physics of the scattering process so that we can optimize these nanostructures for applications. ![Picture of blue, green, and red photonic capsules](/sites/g/files/omnuum4256/files/manoharan/files/redgreenblue_photonic_microcapsules.jpg) We are particularly interested in making structural color that is *angle independent.* That means that the color is the same, regardless of how you rotate the material, and regardless of the angle between the light source and your eyes. There are many structurally colored materials that, like an opal stone, are iridescent, meaning that the color changes with the viewing angle and orientation. The reason for this change in color is that the nanostructure of these materials is well-ordered (or crystalline). Sometimes these kinds of ordered structures are called photonic crystals. To make materials that have angle-independent color, we need to make nanostructures that are disordered. We call these materials *photonic glasses* (a term that we believe was first coined by [John Ballato in 2000](http://dx.doi.org/10.1364/JOSAB.17.000219)). Examples of naturally occurring photonic glasses are the feathers of blue birds and the wings of blue butterflies. [Eric Dufresne](http://www.eng.yale.edu/softmatter/) and collaborators were the first to demonstrate synthetic structures that mimic the blue color of the bird feathers ([Forster, Noh, Liew, Saranathan, Schreck, Yang, Park, Prum, Mochrie, O'Hern, Cao, Dufresne *Advanced Materials* 2010)](http://dx.doi.org/10.1002/adma.200903693). They made these structures from spherical colloidal particles, and they taught us their techniques. Our goal is to study, both theoretically and experimentally, how the optical properties of these glasses relate to their structure and constituent particles. Based on our observations from photonic glasses of conventional particles, we constructed a theoretical model that explains why it is difficult to make yellow, orange, and red photonic glasses. Guided by this model, we have developed new colloidal systems that give a higher degree of control over structural color. These systems might be used to make reflective displays or paints and coatings. ## Understanding why blue structural colors are easier to make than red Early in our work on angle-independent structural color, we found that it was easy to make blue colors but hard to make yellow, orange, or red. It also turns out that nearly all examples of angle-independent color in nature are blue. [Sofia Magkiriadou](/people/sofia-magkiriadou) and [Jin-Gyu Park](/people/jin-gyu-park) set out to understand why. Sofia made photonic glasses of different particle sizes and showed that the wavelength of the structural color scaled with the size of the particle, as expected. She was able to make blue and green samples, but the sample that should have been red turned out to be magenta: ![replot_b_g_p_images.png](/sites/g/files/omnuum4256/files/manoharan/files/replot_b_g_p_images.png) At left, measured reflectivity spectra for three similarly prepared colloidal glasses of PMMA particles in air. Photographs of the samples are shown at right. The magenta sample would appear red if it weren't for the high reflectivity in the blue, indicated by the arrow in the spectra. Sofia developed a theoretical model to explain the blue peak in the reflectivity spectrum that, when mixed with the red structural color, made these samples magenta. She showed that this blue peak arises because the individual colloidal particles tend to scatter light more strongly in the blue than in the red (the same argument can be used to explain why the sky is blue). More technically, she and her colleagues showed how the backscattering resonances of the individual particles arise from cavity modes and how these resonances interact with the constructive interference of the nanostructures to suppress the structural red color. From the model that Sofia developed, we were able to establish some design rules for making red structural color. Our findings were highlighted in [*Physics*](http://physics.aps.org/synopsis-for/10.1103/PhysRevE.90.062302)*,* [*New Scientist*](https://www.newscientist.com/article/dn26687-light-trickery-makes-bird-feathers-blue-but-not-red)*,* and [*Chemistry World*](http://www.rsc.org/chemistryworld/2015/01/mystery-why-structural-red-colour-not-found-nature-solved-e-reader). **Making angle-independent red structural colors** Based on the design rules established in our theoretical study, our group is trying to make *photonic pigments* that are non-fading and non-toxic: these pigments can potentially be used in cosmetics, reflective displays, and inks. Jin-Gyu Park, working together with Sofia and Shin-Hyun Kim, were able to demonstrate a colloidal assembly method to make microcapsules that showed non-iridescent structural colors spanning the entire visible range. The microcapsules are made using a microfluidic device that produces a droplet surrounded by a thin shell of monomer. The droplet contains colloidal particles with a core-shell structure, the core consisting of polystyrene, which has a high-refractive index, and the shell consisting of a hydrogel, which has a low refractive index. The core-shell structures of the particles allows us to decouple the distance between the particles, which sets the structural color, from the scattering strength of the individual particles, which sets the opacity (to understand this, have a look at one of our [earlier papers](/publications/disordered-Packings-Core-Shell-Particles-Angle-Independent-Structural-Colors)). After making the droplets, Jin-Gyu and colleagues were able to concentrate the core-shell particles into a dense, disordered nanostructure by pulling out the water. Then they polymerized the shell to make photonic capsules: ![compression_scheme_internal_structure.png](/sites/g/files/omnuum4256/files/manoharan/files/compression_scheme_internal_structure.png) Top photographs show a droplet containing core-shell scatterers. By removing the water, as shown in the diagram at bottom, we concentrate the particles. The color of the droplet becomes more yellow as the particles get more concentrated. We can then lock in the structure by polymerizing the shell, creating a photonic capsule. The electron microscope image at bottom right shows the random and isotropic nanostructure formed by the core-shell particles inside the capsule. By changing the sizes of the cores and the shells, Jin-Gyu and colleagues were able to make photonic capsules with blue, green, and red colors: ![Picture of blue, green, and red photonic capsules](/sites/g/files/omnuum4256/files/manoharan/files/redgreenblue_photonic_microcapsules.jpg) Our results were highlighted in [*Phys.org*](http://phys.org/news/2014-02-non-iridescent-full-spectrum-pigments.html), [*Chemical & Engineering News*](http://cen.acs.org/articles/92/i17/Colloids-Yield-Full-Color-Palette.html), [*Harvard Magazine*](http://harvardmagazine.com/2014/07/crafting-color)*,* and in a [press release](http://www.seas.harvard.edu/news/2014/03/brighter-inks-without-pigment) from Harvard SEAS. ## Materials with responsive structural color [Jin-Gyu Park](/people/jin-gyu-park) and [Ben Rogers](/people/w-benjamin-rogers) realized that the hydrogel core-shell particles we were using to make the photonic capsules could also be used to make responsive structural color, that is, color that can change with solution conditions or temperature. They made the photonic crystals shown below, which can shift their color rapidly in response to temperature. These materials might be used as sensors or as resonators for organic lasers. ![web_3rd_project_scheme.png](/sites/g/files/omnuum4256/files/manoharan/files/web_3rd_project_scheme.png) Colloidal photonic crystals made of hydrogel building blocks can rapidly change colors without melting ## Publications Download 17 citations download- [BibTeX](/bibcite/export?pager_style=no_pager&number_of_items=30&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchareas%5D%5B0%5D%5Btarget_id%5D=14691&&&format=bibtex) - [EndNote X3 XML](/bibcite/export?pager_style=no_pager&number_of_items=30&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchareas%5D%5B0%5D%5Btarget_id%5D=14691&&&format=endnote8) - [EndNote 7 XML](/bibcite/export?pager_style=no_pager&number_of_items=30&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchareas%5D%5B0%5D%5Btarget_id%5D=14691&&&format=endnote7) - [Endnote tagged](/bibcite/export?pager_style=no_pager&number_of_items=30&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchareas%5D%5B0%5D%5Btarget_id%5D=14691&&&format=tagged) - [Marc](/bibcite/export?pager_style=no_pager&number_of_items=30&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchareas%5D%5B0%5D%5Btarget_id%5D=14691&&&format=marc) - [PubMedId](/bibcite/export?pager_style=no_pager&number_of_items=30&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchareas%5D%5B0%5D%5Btarget_id%5D=14691&&&format=pubmed_id) - [RIS](/bibcite/export?pager_style=no_pager&number_of_items=30&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_researchareas%5D%5B0%5D%5Btarget_id%5D=14691&&&format=ris) ### 2022 Xiao, M.; Mao, J.; Kollosche, M.; Hwang, V.; Clarke, D.; Manoharan, V. N. [Voltage-Tunable Elastomer Composites That Use Shape Instabilities for Rapid Structural Color Changes](/publications/voltage-tunable-elastomer-composites-use-shape-instabilities-rapid-structural). *Materials Horizons* **2022**, *9* (7), 1954-1961. Xiao, M.; Mao, J.; Kollosche, M.; Hwang, V.; Clarke, D.; Manoharan, V. N. [Voltage-Tunable Elastomer Composites That Use Shape Instabilities for Rapid Structural Color Changes](/publications/voltage-tunable-elastomer-composites-use-shape-instabilities-rapid-structural). *Materials Horizons* **2022**, *9* (7), 1954-1961. - [ descriptionPublisher's Version](https://pubs.rsc.org/en/content/articlelanding/2022/mh/d2mh00374k/unauth) - [ descriptionPublisher's Version](https://pubs.rsc.org/en/content/articlelanding/2022/mh/d2mh00374k/unauth) Stephenson, A. B.; Xiao, M.; Hwang, V.; Qu, L.; Odorisio, P. A.; Burke, M.; Task, K.; Deisenroth, T.; Barkley, S.; Darji, R. H.; Manoharan, V. N. [Predicting the Structural Colors of Films of Disordered Photonic Balls](/publications/predicting-structural-colors-films-disordered-photonic-balls). *ACS Photonics* **2022**, *10* (1), 58-70. Stephenson, A. B.; Xiao, M.; Hwang, V.; Qu, L.; Odorisio, P. A.; Burke, M.; Task, K.; Deisenroth, T.; Barkley, S.; Darji, R. H.; Manoharan, V. N. [Predicting the Structural Colors of Films of Disordered Photonic Balls](/publications/predicting-structural-colors-films-disordered-photonic-balls). *ACS Photonics* **2022**, *10* (1), 58-70. - [ descriptionPublisher's Version](https://pubs.acs.org/doi/abs/10.1021/acsphotonics.2c00892) - [ descriptionPublisher's Version](https://pubs.acs.org/doi/abs/10.1021/acsphotonics.2c00892) ### 2021 Manoharan, V. N.; Stephenson, A. B. [A Field Guide to Angle-Independent Structural Color](/publications/field-guide-angle-independent-structural-color). *Physics Today*. 2021, pp. 62-63. Manoharan, V. N.; Stephenson, A. B. [A Field Guide to Angle-Independent Structural Color](/publications/field-guide-angle-independent-structural-color). *Physics Today*. 2021, pp. 62-63. - [ descriptionPublisher's Version](https://pubs.aip.org/physicstoday/article-abstract/74/1/62/396298/A-field-guide-to-angle-independent-structural) - [ descriptionPublisher's Version](https://pubs.aip.org/physicstoday/article-abstract/74/1/62/396298/A-field-guide-to-angle-independent-structural) Hwang, V.; Stephenson, A. B.; Barkley, S.; Brandt, S.; Xiao, M.; Aizenberg, J.; Manoharan, V. N. [Designing Angle-Independent Structural Colors Using Monte Carlo Simulations of Multiple Scattering](https://www.pnas.org/doi/abs/10.1073/pnas.2015551118). *Proceedings of the National Academy of Sciences* **2021**, *118* (4), e2015551118. Hwang, V.; Stephenson, A. B.; Barkley, S.; Brandt, S.; Xiao, M.; Aizenberg, J.; Manoharan, V. N. [Designing Angle-Independent Structural Colors Using Monte Carlo Simulations of Multiple Scattering](https://www.pnas.org/doi/abs/10.1073/pnas.2015551118). *Proceedings of the National Academy of Sciences* **2021**, *118* (4), e2015551118. Xiao, M.; Stephenson, A. B.; Neophytou, A.; Hwang, V.; Chakrabarti, D.; Manoharan, V. N. [Investigating the Trade-off Between Color Saturation and Angle-Independence in Photonic Glasses](/publications/investigating-trade-between-color-saturation-and-angle-independence-photonic). *Optics Express* **2021**, *29* (14), 21212-21224. Xiao, M.; Stephenson, A. B.; Neophytou, A.; Hwang, V.; Chakrabarti, D.; Manoharan, V. N. [Investigating the Trade-off Between Color Saturation and Angle-Independence in Photonic Glasses](/publications/investigating-trade-between-color-saturation-and-angle-independence-photonic). *Optics Express* **2021**, *29* (14), 21212-21224. - [ descriptionPublisher's Version](https://opg.optica.org/oe/fulltext.cfm?uri=oe-29-14-21212&id=452661) - [ descriptionPublisher's Version](https://opg.optica.org/oe/fulltext.cfm?uri=oe-29-14-21212&id=452661) ### 2020 Hwang, V.; Stephenson, A. B.; Magkiriadou, S.; Park, J.-G.; Manoharan, V. N. [Effects of Multiple Scattering on Angle-Independent Structural Color in Disordered Colloidal Materials](/publications/effects-multiple-scattering-angle-independent-structural-color-disordered). *Physical Review E* **2020**, *101* (1), 012614. Hwang, V.; Stephenson, A. B.; Magkiriadou, S.; Park, J.-G.; Manoharan, V. N. [Effects of Multiple Scattering on Angle-Independent Structural Color in Disordered Colloidal Materials](/publications/effects-multiple-scattering-angle-independent-structural-color-disordered). *Physical Review E* **2020**, *101* (1), 012614. - [ descriptionPublisher's Version](https://journals.aps.org/pre/abstract/10.1103/PhysRevE.101.012614) - [ descriptionPublisher's Version](https://journals.aps.org/pre/abstract/10.1103/PhysRevE.101.012614) Kim, C.; Jung, K.; Yu, J. W.; Park, S.; Kim, S.-H.; Lee, W. B.; Hwang, H.; Manoharan, V. N.; Moon, J. H. [Controlled Assembly of Icosahedral Colloidal Clusters for Structural Coloration](/publications/controlled-assembly-icosahedral-colloidal-clusters-structural-coloration). *Chemistry of Materials* **2020**, *32* (22), 9704-9712. Kim, C.; Jung, K.; Yu, J. W.; Park, S.; Kim, S.-H.; Lee, W. B.; Hwang, H.; Manoharan, V. N.; Moon, J. H. [Controlled Assembly of Icosahedral Colloidal Clusters for Structural Coloration](/publications/controlled-assembly-icosahedral-colloidal-clusters-structural-coloration). *Chemistry of Materials* **2020**, *32* (22), 9704-9712. - [ descriptionPublisher's Version](https://pubs.acs.org/doi/abs/10.1021/acs.chemmater.0c03391) - [ descriptionPublisher's Version](https://pubs.acs.org/doi/abs/10.1021/acs.chemmater.0c03391) ### 2017 Park, J.-G.; Rogers, W. B.; Magiriadou, S.; Kodger, T.; Kim, S.-H.; Kim, Y.-S.; Manoharan, V. N. [Photonic-Crystal Hydrogels With a Rapidly Tunable Stop Band and High Reflectivity across the Visible](/publications/photonic-crystal-hydrogels-rapidly-tunable-stop-band-and-high-reflectivity). *Optical Materials Express* **2017**, *7* (1), 253-263. Park, J.-G.; Rogers, W. B.; Magiriadou, S.; Kodger, T.; Kim, S.-H.; Kim, Y.-S.; Manoharan, V. N. [Photonic-Crystal Hydrogels With a Rapidly Tunable Stop Band and High Reflectivity across the Visible](/publications/photonic-crystal-hydrogels-rapidly-tunable-stop-band-and-high-reflectivity). *Optical Materials Express* **2017**, *7* (1), 253-263. - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](http://dx.doi.org/10.1364/OME.7.000253) - [ picture\_as\_pdfPark et al. - 2017 - Phot...](/sites/g/files/omnuum4256/files/manoharan/files/park_et_al._-_2017_-_photonic-crystal_hydrogels_with_a_rapidly_tunable_stop_band.pdf) We present a new type of hydrogel photonic crystal with a stop band that can be rapidly modulated across the entire visible spectrum. We make these materials by using a high-molecular-weight polymer to induce a depletion attraction between polystyrene... - [ descriptionPublisher's Version](http://dx.doi.org/10.1364/OME.7.000253) - [ picture\_as\_pdfPark et al. - 2017 - Phot...](/sites/g/files/omnuum4256/files/manoharan/files/park_et_al._-_2017_-_photonic-crystal_hydrogels_with_a_rapidly_tunable_stop_band.pdf) Manoharan, V.; Magkiriadou, S.; Park, J.-G. [United States Patent 9541674: Photonic Balls Containing a Microstructure of Core-Shell Particles Exhibiting Angularly-Independent Structural Color](/publications/photonic-balls-containing-microstructure-core-shell-particles-exhibiting-0), 2017. Manoharan, V.; Magkiriadou, S.; Park, J.-G. [United States Patent 9541674: Photonic Balls Containing a Microstructure of Core-Shell Particles Exhibiting Angularly-Independent Structural Color](/publications/photonic-balls-containing-microstructure-core-shell-particles-exhibiting-0), 2017. - [ descriptionPublisher's Version](http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=1&f=G&l=50&co1=AND&d=PTXT&s1=9,541,674.PN.&OS=PN/9,541,674&RS=PN/9,541,674) - [ descriptionPublisher's Version](http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=1&f=G&l=50&co1=AND&d=PTXT&s1=9,541,674.PN.&OS=PN/9,541,674&RS=PN/9,541,674) Kim, S.-H.; Magkiriadou, S.; Rhee, D. K.; Lee, D. S.; Yoo, P. J.; Manoharan, V. N.; Yi, G.-R. [Inverse Photonic Glasses by Packing Bidisperse Hollow Microspheres With Uniform Cores](/publications/inverse-photonic-glasses-packing-bidisperse-hollow-microspheres-uniform-cores). *ACS Applied Materials & Interfaces* **2017**, *9* (28), 24155-24160. Kim, S.-H.; Magkiriadou, S.; Rhee, D. K.; Lee, D. S.; Yoo, P. J.; Manoharan, V. N.; Yi, G.-R. [Inverse Photonic Glasses by Packing Bidisperse Hollow Microspheres With Uniform Cores](/publications/inverse-photonic-glasses-packing-bidisperse-hollow-microspheres-uniform-cores). *ACS Applied Materials & Interfaces* **2017**, *9* (28), 24155-24160. - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](http://dx.doi.org/10.1021/acsami.7b02098) - [ picture\_as\_pdfKim et al. - 2017 - Inver...](/sites/g/files/omnuum4256/files/manoharan/files/kim_et_al._-_2017_-_inverse_photonic_glasses_by_packing_bidisperse_hollow_spheres.pdf) A major fabrication challenge is producing disordered photonic materials with an angle-independent structural red color. Theoretical work has shown that such a color can be produced by fabricating inverse photonic glasses with monodisperse, nontouching... - [ descriptionPublisher's Version](http://dx.doi.org/10.1021/acsami.7b02098) - [ picture\_as\_pdfKim et al. - 2017 - Inver...](/sites/g/files/omnuum4256/files/manoharan/files/kim_et_al._-_2017_-_inverse_photonic_glasses_by_packing_bidisperse_hollow_spheres.pdf) ### 2015 Choi, T. M.; Park, J.-G.; Kim, Y.-S.; Manoharan, V. N.; Kim, S.-H. [Osmotic-Pressure-Mediated Control of Structural Colors of Photonic Capsules](/publications/osmotic-pressure-mediated-control-structural-colors-photonic-capsules). *Chemistry of Materials* **2015**, *27* (3), 1014–1020. Choi, T. M.; Park, J.-G.; Kim, Y.-S.; Manoharan, V. N.; Kim, S.-H. [Osmotic-Pressure-Mediated Control of Structural Colors of Photonic Capsules](/publications/osmotic-pressure-mediated-control-structural-colors-photonic-capsules). *Chemistry of Materials* **2015**, *27* (3), 1014–1020. - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](http://dx.doi.org/10.1021/cm5043292) - [ picture\_as\_pdfChoi\_ChemMater\_2015.pdf](/sites/g/files/omnuum4256/files/manoharan/files/choi_et_al._-_2015_-_osmotic-pressure-mediated_control_of_structural_co.pdf) - [ picture\_as\_pdfChoi\_ChemMater\_2015-Suppl...](/sites/g/files/omnuum4256/files/manoharan/files/si_-_choi_et_al._-_2015_-_osmotic-pressure-mediated_control_of_structural_co.pdf) Crystalline or glassy materials made of colloidal nanoparticles show distinctive photonic effects; the crystals exhibit sparkling colors with strong iridescence, while the glasses show noniridescent colors. Both colors are the results of constructive... - [ descriptionPublisher's Version](http://dx.doi.org/10.1021/cm5043292) - [ picture\_as\_pdfChoi\_ChemMater\_2015.pdf](/sites/g/files/omnuum4256/files/manoharan/files/choi_et_al._-_2015_-_osmotic-pressure-mediated_control_of_structural_co.pdf) - [ picture\_as\_pdfChoi\_ChemMater\_2015-Suppl...](/sites/g/files/omnuum4256/files/manoharan/files/si_-_choi_et_al._-_2015_-_osmotic-pressure-mediated_control_of_structural_co.pdf) Magkiriadou, S. [Structural Color From Colloidal Glasses](/publications/structural-color-colloidal-glasses), 2015. Magkiriadou, S. [Structural Color From Colloidal Glasses](/publications/structural-color-colloidal-glasses), 2015. - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](http://dash.harvard.edu/handle/1/14226099) When a material has inhomogeneities at a lengthscale comparable to the wavelength of light, interference can give rise to structural colors: colors that originate from the interaction of the material's microstructure with light and do not require... - [ descriptionPublisher's Version](http://dash.harvard.edu/handle/1/14226099) ### 2014 Park, J.-G.; Kim, S.-H.; Magkiriadou, S.; Choi, T. M.; Kim, Y.-S.; Manoharan, V. [Full-Spectrum Photonic Pigments With Non-Iridescent Structural Colors through Colloidal Assembly](/publications/full-spectrum-photonic-pigments-non-iridescent-structural-colors-through). *Angewandte Chemie International Edition* **2014**, *53* (11), 2899-2903. Park, J.-G.; Kim, S.-H.; Magkiriadou, S.; Choi, T. M.; Kim, Y.-S.; Manoharan, V. [Full-Spectrum Photonic Pigments With Non-Iridescent Structural Colors through Colloidal Assembly](/publications/full-spectrum-photonic-pigments-non-iridescent-structural-colors-through). *Angewandte Chemie International Edition* **2014**, *53* (11), 2899-2903. - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](http://dx.doi.org/10.1002/anie.201309306) Structurally colored materials could potentially replace dyes and pigments in many applications, but it is challenging to fabricate structural colors that mimic the appearance of absorbing pigments. We demonstrate the microfluidic fabrication of “photonic... - [ descriptionPublisher's Version](http://dx.doi.org/10.1002/anie.201309306) Kim, S.-H.; Park, J.-G.; Choi, T. M.; Manoharan, V.; Weitz, D. [ Osmotic-Pressure-Controlled Concentration of Colloidal Particles in Thin-Shelled Capsules ](/publications/osmotic-pressure-controlled-concentration-colloidal-particles-thin-shelled). *Nature Communications* **2014**, *5*, 3068. Kim, S.-H.; Park, J.-G.; Choi, T. M.; Manoharan, V.; Weitz, D. [ Osmotic-Pressure-Controlled Concentration of Colloidal Particles in Thin-Shelled Capsules ](/publications/osmotic-pressure-controlled-concentration-colloidal-particles-thin-shelled). *Nature Communications* **2014**, *5*, 3068. - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](http://dx.doi.org/10.1038/ncomms4068) Colloidal crystals are promising structures for photonic applications requiring dynamic control over optical properties. However, for ease of processing and reconfigurability, the crystals should be encapsulated to form ‘ink’ capsules rather than confined... - [ descriptionPublisher's Version](http://dx.doi.org/10.1038/ncomms4068) Magkiriadou, S.; Park, J.-G.; Kim, Y.-S.; Manoharan, V. [Absence of Red Structural Color in Photonic Glasses, Bird Feathers, and Certain Beetles](/publications/absence-red-structural-color-photonic-glasses-bird-feathers-and-certain). *Physical Review E* **2014**, *90*, 062302. Magkiriadou, S.; Park, J.-G.; Kim, Y.-S.; Manoharan, V. [Absence of Red Structural Color in Photonic Glasses, Bird Feathers, and Certain Beetles](/publications/absence-red-structural-color-photonic-glasses-bird-feathers-and-certain). *Physical Review E* **2014**, *90*, 062302. - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](http://dx.doi.org/10.1103/PhysRevE.90.062302) Colloidal glasses, bird feathers, and beetle scales can all show structural colors arising from short-ranged spatial correlations between scattering centers. Unlike the structural colors arising from Bragg diffraction in ordered materials like opals, the... - [ descriptionPublisher's Version](http://dx.doi.org/10.1103/PhysRevE.90.062302) Manoharan, V.; Magkiriadou, S.; Park, J.-G. [Photonic Balls Containing a Microstructure of Core-Shell Particles Exhibiting Angularly-Independent Structural Color](/publications/photonic-balls-containing-microstructure-core-shell-particles-exhibiting), 2014. Manoharan, V.; Magkiriadou, S.; Park, J.-G. [Photonic Balls Containing a Microstructure of Core-Shell Particles Exhibiting Angularly-Independent Structural Color](/publications/photonic-balls-containing-microstructure-core-shell-particles-exhibiting), 2014. - add\_circle\_outline do\_not\_disturb\_on Abstract A photonic assembly for observing a preselected color includes an assembly of colloidal particles in a continuous liquid phase, the colloidal particles comprising a core scattering center and a shell layer surrounding the core, wherein the core scattering... ### 2012 Magkiriadou, S.; Park, J.-G.; Kim, Y.-S.; Manoharan, V. [ Disordered Packings of Core-Shell Particles With Angle-Independent Structural Colors ](/publications/disordered-packings-core-shell-particles-angle-independent-structural-colors). *Optical Materials Express* **2012**, *2* (10), 1343-1352. Magkiriadou, S.; Park, J.-G.; Kim, Y.-S.; Manoharan, V. [ Disordered Packings of Core-Shell Particles With Angle-Independent Structural Colors ](/publications/disordered-packings-core-shell-particles-angle-independent-structural-colors). *Optical Materials Express* **2012**, *2* (10), 1343-1352. - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](http://dx.doi.org/10.1364/OME.2.001343) Making materials that display angle-independent structural color requires control over both scattering and short-range correlations in the refractive index. We demonstrate a simple way to make such materials by packing core-shell colloidal particles... - [ descriptionPublisher's Version](http://dx.doi.org/10.1364/OME.2.001343) ## Project team [### Alexa Fein ](/people/alexa-fein) Alexa is an undergraduate student majoring in physics. She works with Audrey on the structural color project exploring applications in plastic packaging. Alexa loves yoga and greek yogurt. ![Alexa headshot](/sites/g/files/omnuum4256/files/styles/hwp_4_5__690x865/public/2025-09/IMG_2930.jpeg?h=df844158&itok=8-Jo2psz) [### Angela Tang ](/people/angela-tang) Angela is a graduate student in Applied Physics. She works on the structural color project. Angela enjoys baking and water sports. ![Angela picture](/sites/g/files/omnuum4256/files/styles/hwp_4_5__690x865/public/2025-09/Screenshot%202025-09-24%20at%2014.56.13.png?h=4fe4d3c6&itok=aL3X-R65) [### Audrey von Raesfeld ](/people/audrey-von-raesfeld) Graduate Student Audrey is a PhD candidate in Applied Physics whose research explores the structural color and optical properties of disordered macroporous photonic materials. A central focus of her work has been developing scalable fabrication methods that bring these... ![audrey_headshot_2025](/sites/g/files/omnuum4256/files/styles/hwp_4_5__690x865/public/2025-12/251203_headshot.jpg?h=e1454870&itok=WbgQ1AP_) [### Brandon Chyi ](/people/brandon-chyi) Brandon is a Ph.D Student in Chemistry and Chemical Biology. He is interested in the interactions between physical structure and chemical composition in materials which give rise to color. Outside of lab he loves to cook and take care of his plants and... ![Brandon Chyi](/sites/g/files/omnuum4256/files/styles/hwp_4_5__690x865/public/2025-11/WIN_20241119_04_59_44_Pro.jpg?itok=OUaJ_dVL) [### Dalilah Mostoslavsky ](/people/dalilah-mostoslavsky) Dalilah is a graduate student in the Applied Physics department. She is studying interactions between scattering and absorption in structurally colored systems. Dalilah loves baking and horror movies. ![Dalilah headshot](/sites/g/files/omnuum4256/files/styles/hwp_4_5__690x865/public/2025-09/IMG_7137.jpg?h=b459a4db&itok=iJkbm3n-) ## Alumni [### Annie Stephenson ](/people/annie-stephenson) PhD Applied Physics 2022 Annie was a PhD student in Applied Physics who studied light scattering in disordered systems such as colloidal glasses. Her work focused on understanding how the degree of order in nanoscale structures affects their scattering and structural color. She... ![Annie Stephenson](/sites/g/files/omnuum4256/files/styles/hwp_4_5__690x865/public/manoharan/files/4.15.15_anna_stephenson_6441.jpg?itok=gTztywki) [### Jennifer McGuire ](/people/jennifer-mcguire) PhD Applied Physics 2025 Jennifer was a PhD student in Applied Physics. She studied light transport through a variety of materials – including semiconductor nanowires, structurally colored colloidal assemblies, and grease films – using both computational and experimental... ![Jennifer McGuire](/sites/g/files/omnuum4256/files/styles/hwp_4_5__690x865/public/manoharan/files/jennifer_headshot.jpg?itok=quIuTFB_) [### Jin-Gyu Park ](/people/jin-gyu-park)Former research associate Jin-Gyu was a research associate who studied structural colors made through self-assembly of colloidal particles. He received his BS (1995) and MS (1997) in the Department of Industrial Chemistry engineering from Hanyang University in 2002. He then worked... ![Jin-Gyu](/sites/g/files/omnuum4256/files/styles/hwp_4_5__690x865/public/manoharan/files/img_1952.jpg?itok=imMLGZb5) [### Sofia Magkiriadou ](/people/sofia-magkiriadou)PhD Physics 2014 Sofia was a PhD student in Physics working on the physics of structural color. She earned her PhD in 2014. ![Sofia](/sites/g/files/omnuum4256/files/styles/hwp_4_5__690x865/public/manoharan/files/picture1.jpg?itok=x1L0udXI) [### Victoria Hwang ](/people/victoria-hwang) PhD Applied Physics 2020 Victoria was PhD student in Applied Physics studying the self-assembly of amorphous colloidal photonic materials. She focused on designing novel techniques for creating structurally-colored films, with an emphasis on expanding the range of colors and... ![Victoria](/sites/g/files/omnuum4256/files/styles/hwp_4_5__690x865/public/manoharan/files/img_1025_copy_1.jpg?itok=xypd50Jh) See also:- [ Current research areas ](/research-areas/current-research-areas) - [ Structural color ](/research-areas/structural-color) - [ Project descriptions ](/page-categories/project-descriptions)