An official website of the United States government
Spectral selectivity is of interest for many photovoltaic applications, such as in multijunction and transparent solar cells, where wavelength-selectivity of the photoactive material is necessary. We investigate using artificial photonic band engineering as a method for achieving spectral selectivity in an absorbing material such as PbS CQD thin films. Using FDTD simulations, we find that a CQD-based photonic crystal (CQD-PC) is able to maintain its photonic band structure, including the existence of a reduced photonic density of states, in the presence of weak material absorption. This shows that CQD-PCs are a promising material for photovoltaic applications that require spectral selectivity.
more »
« less
Controlling spectral selectivity in optoelectronics via photonic band engineering in absorbing media
The most common solution for achieving arbitrary spectral selectivity in optoelectronic devices is adding external filters. Here we propose using semiconductor thin film photonic crystals with relevant photonic bands that fall within the absorbing frequency range of the material for spectral selectivity. Optical simulations show that the in-plane photonic bands couple strongly to normal-incidence external fields, inducing tunable resonance features in the out-of-plane transmission and reflection spectra. Experimentally, we fabricate a proof-of-principle photonic structure with enhanced visible transparency, consisting of a self-assembled polystyrene bead array infiltrated with colloidal quantum dots, showing promise for multijunction and transparent photovoltaics.
more »
« less
- Award ID(s):
- 1846239
- PAR ID:
- 10136881
- Date Published:
- Journal Name:
- Controlling spectral selectivity in optoelectronics via photonic band engineering in absorbing media
- Page Range / eLocation ID:
- 1 to 5
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
In the recent years, photonic Chern materials have attracted substantial interest as they feature topological edge states that are robust against disorder, promising to realize defect-agnostic integrated photonic crystal slab devices. However, the out-of-plane radiative losses in those photonic Chern slabs has been previously neglected, yielding limited accuracy for predictions of these systems’ topological protection. Here, we develop a general framework for measuring the topological protection in photonic systems, such as in photonic crystal slabs, while accounting for in-plane and out-of-plane radiative losses. Our approach relies on the spectral localizer that combines the position and Hamiltonian matrices of the system to draw a real-picture of the system’s topology. This operator-based approach to topology allows us to use an effective Hamiltonian directly derived from the full-wave Maxwell equations after discretization via finite-elements method (FEM), resulting in the full account of all the system’s physical processes. As the spectral FEM-localizer is constructed solely from FEM discretization of the system’s master equation, the proposed framework is applicable to any physical system and is compatible with commonly used FEM software. Moving forward, we anticipate the generality of the method to aid in the topological classification of a broad range of complex physical systems.more » « less
-
In this paper, we present the results of numerical simulations of the optical spectra of a three-sphere photonic molecule. The configuration of the system was continuously modified from linear to triangular, in-plane with the fundamental mode excited in one of the spheres and perpendicular to it. We found the relative insensitivity of the spectra to the in-plane deviation from the linear arrangement up to about 110°. For larger angles, the spectra show significant modification consisting of the major spectral peaks splitting and shifting. On the contrary, the spectra are quite sensitive to out-of-plane molecule deviation, even at small angles. Thus, the spectra of photonic molecules can be modified by changing the mutual positions of the constituent resonators, which can be useful in reconfigurable photonic devices.more » « less
-
Microresonator frequency combs and their design versatility have revolutionized research areas from data communication to exoplanet searches. While microcombs in the 1550 nm band are well documented, there is interest in using microcombs in other bands. Here, we demonstrate the formation and spectral control of normal-dispersion dark soliton microcombs at 1064 nm. We generate 200 GHz repetition rate microcombs by inducing a photonic bandgap of the microresonator mode for the pump laser with a photonic crystal. We perform the experiments with normal-dispersion microresonators made from Ta2O5 and explore unique soliton pulse shapes and operating behaviors. By adjusting the resonator dispersion through its nanostructured geometry, we demonstrate control over the spectral bandwidth of these combs, and we employ numerical modeling to understand their existence range. Our results highlight how photonic design enables microcomb spectra tailoring across wide wavelength ranges, offering potential in bioimaging, spectroscopy, and photonic-atomic quantum technologies.more » « less
-
Schmidt, Dirk; Schreiber, Laura; Vernet, Elise (Ed.)Inner working angle is a key parameter for enabling scientific discovery in direct exoplanet imaging and characterization. Approaches to improving the inner working angle to reach the diffraction limit center on the sensing and control of wavefront errors, starlight suppression via coronagraphy, and differential techniques applied in post-processing. These approaches are ultimately limited by the shot noise of the residual starlight, placing a premium on the ability of the adaptive optics system to sense and control wavefront errors so that the coronagraph can effectively suppress starlight reaching the science focal plane. Photonic lanterns are attractive for use in the science focal plane because of their ability to spatially filter light using a finite basis of accepted modes and effectively couple the results to diffraction-limited spectrometers, providing a compact and cost-effective means to implement post-processing based on spectral diversity. We aim to characterize the ability of photonic lanterns to serve as focal-plane wavefront sensors, allowing the adaptive optics system to control aberrations affecting the science focal plane and reject additional stellar photon noise. By serving as focal-plane wavefront sensors, photonic lanterns can improve sensitivity to exoplanets through both direct and coronagraphic observations. We have studied the sensing capabilities of photonic lanterns in the linear and quadratic regimes with analytical and numerical treatments for different lantern geometries (including non-mode-selective, mode-selective, and hybrid geometries) as a function of port number. In this presentation we report on the sensitivity of such lanterns and comment on the relative suitability and sensitivity impacts of different lantern geometries for focal-plane wavefront sensing.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/CISS.2019.8692845
