Review of nanostructure color filters

Abstract

Nanostructure color filters filter light spectrum via the structural engineering, unlike traditional dye filters that rely on the chemical compositions to absorb light. In light of the successful advance in micro/nanofabrication technology in the past decades, these structured color filters are particularly promising for future applications in ultrascaled color filtering and multispectral imaging. We will summarize the recent progress in nanostructure color filters based on plasmonics, nanowires, metamaterials, and quantum dots (QDs). Plasmonics filters rely on surface plasmon resonances to realize the spectrum selection. For nanowire color filters, the color filtering is achieved by light coupling into the leaky or waveguiding mode in nanowires. In metamaterial filters, the refractive index of artificial materials is manipulated to create a broad color palette. QDs color filters rely on bandgap engineering to create filtering effects by simply altering the size and composition of the QDs. Clearly, the above filtering technologies have their own pros and cons, which will be analyzed.

3D-printed miniature spectrometer for the visible range with a 100 × 100 μm² footprint

“…Furthermore, the implementation of a spectrometer fabricated strictly by 3D printing can be highlighted as a novelty. The measured ratio of bandwidth per resolution of is in a margin similar to those of other spectrometers that have been demonstrated in this size range 29,31 . In the category of direct spectrometers, the microspectrometer presented here is the first of its kind in this size range (see Fig.…”

“…It is our understanding that only two spectrometers have been demonstrated in which the system sizes are of the same order of magnitude as our footprint of 100 × 100 μm 2 . They are based on nanowires 29,30 or disordered photonic structures 31 , and they have a bandwidth per resolution ratio that is similar to the one in our approach. However, owing to wavelength multiplexing, the system must be calibrated with an iterative reconstruction algorithm to deduce the original spectrum.…”

Bias‐Modulated Multicolor Discrimination Enabled by an Organic–Inorganic Hybrid Perovskite Photodetector with a p‐i‐n‐i‐p Configuration

“…[ 1,2 ] General building blocks in photodetection systems include broadband photoactive materials and dissipative optical filters for estimating not only the brightness of illuminated light but also its spectral information. [ 3 ] However, the rigorous and scalable integration of optical filters on top of the prefabricated detectors leads to time‐consuming and sophisticated alignment steps, consequently increasing the device cost. [ 4,5 ] Furthermore, the considerable light loss (approximately two‐thirds of the light intensity) originating from light absorption by the color filters reduces the sensitivity of the systems.…”

“…Photodetectors with narrowband absorbers (e.g., quantum dots) or plasmonic gratings are commonly used to realize filter‐free light detection. [ 1,3,5,8,9 ] However, these approaches are typically limited by a trade‐off between a high responsivity (or detectivity) and a narrow spectral response. Recently, organohalide lead perovskite photodetectors with various device configurations (e.g., p‐i‐n or m(metal)‐i‐m) have been intensively studied and exploited as promising FFPs owing to the outstanding optoelectronic properties of highly crystalline perovskites (e.g., high extinction coefficients, small exciton binding energies, long exciton diffusion lengths, and optical gap tuneability).…”

Tunable mid-wave infrared Fabry-Perot bandpass filters using phase-change GeSbTe

“…Nonetheless, for bandpass filters, their transmission response is typically broad with low efficiencies; polarization-dependent multipolar (additional) modes are often excited in the same spectral region, and ultra-high resolution lithographic techniques (e.g. deep /extreme UV) are required for commercial adoption [21][22][23]. For active tunability, integration with electro-optic materials such as LCs [24][25][26] is commonly used.…”