Broadband spectral splitting of light using wavefront shaping

Download

index.pdf

Date

2018

Author

Başay, Yalın

Metadata

Show full item record

Item Usage Stats

197
views

97
downloads

Splitting of light to different frequencies is an important tool for several photonic research and applications. One of those applications is increasing the absorption of light via spectral splitting in solar energy systems. Nowadays, this splitting process is realized by fixed diffraction gratings. However, these structures can't adapt to the environmental changes and their efficiencies differ from season to season. A structure that can adapt to environmental changes would certainly increase the efficiency of solar energy systems. When the dimensions of a medium are comparable to wavelength of light, diffraction plays a major role in wave propagation and it differs by wavelength. Thus, it is possible to obtain intended phase difference for each frequency by changing the thickness or refractive index of the medium. As a result, waves at a specific frequency can be controlled to constructively interfere at a desired point. Liquid crystal displays, which enable to control refractive indices of each pixels via modulating the amplitude of the applied electric field can be used to control diffraction. By this programmable control, the spatial phase of light can be changed between 0-2π and the phase pattern for spectral splitting can be determined. As a result, light can be spectrally split using an adaptive medium. In this thesis, we will use liquid crystal displays to determine a micro structure that can achieve spectral splitting at different angles of incident light. In accordance with this purpose, spectral splitting of light will be customized to a region or a building. In addition, we will also investigate the effectiveness of the spectral splitting and the splitting ratio. Our spectral splitting patterns promise an increase in solar cell efficiency given that the effectiveness will be customized to the location where the solar cell will be positioned.

Subject Keywords

Light., Diffraction., Photonics., Solar cells., Spectrum analysis.

URI

http://etd.lib.metu.edu.tr/upload/12622597/index.pdf
https://hdl.handle.net/11511/27613

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Terahertz (THz) spectroscopy of Freon-11 (CCl3F, CFC-11) at room temperature Altan, Hakan; Alfano, S. A.; Alfano, R. R. (2006-08-31) The rotational spectrum for the lowest vibrational mode for CCl3F has been measured in the 0.1-2 THz frequency range using a compact time-resolved terahertz spectrometer. The peak of the population spectrum for the ground state rotational manifold was observed at 0.3 THz. The observed absorption profile was modeled with rotational and vapor pressure parameters. The limits of detectivity of the compact THz system are discussed in context of atmospheric sensing.
Broadband analogue predistortion using a distortion generator based on two-stage RF mixer topology Nesimoglu, Tayfun (2018-01-01) An analogue predistorter using a distortion generator based on a two-stage radio frequency mixer topology is presented. The proposed distortion generator achieves fundamental signal cancellation without using a signal cancellation loop or a resonant circuit, thus it generates an error signal that predominantly consists of unwanted intermodulation distortion (IMD). Measurements are performed using multi-tones, WLAN- and Terrestrial Trunked Radio (TETRA)-modulated signals. Distortion generator provides high l...
Short term variations of total electron content (TEC) fitting to a regional GPS network over the Kingdom of Saudi Arabia (KSA) Alothman, A. O.; Alsubaie, M. A.; Ayhan, M. E. (Elsevier BV, 2011-09-01) The ionosphere is a dispersive medium for radio waves with the refractive index which is a function of frequency and total electron content (TEC). TEC has a strong diurnal variation in addition to monthly, seasonal and solar cycle variations and small and large scale irregularities. Dual frequency GPS observations can be utilized to obtain TEC and investigate its spatial and temporal variations. We here studied short term TEC variations over the Kingdom of Saudi Arabia (KSA). A regional GPS network is forme...
Broadband Spectral Splitting of Light Using Wavefront Shaping Gün, Berk Nezir; Yüce, Emre (2018-09-12) When the dimensions of a medium are comparable to wavelength of light, diffraction plays a major role in wave propagation and it differs by wavelength. Thus, it is possible to obtain intended phase difference for each frequency by changing the thickness or refractive index of the medium [1]. As a result, waves at a specific frequency can be controlled to constructively interfere at a desired point. Liquid crystal displays, which enable to control refractive indices of each pixels via modulating the ampl...
CMOS LNA design for LEO space S-Band applications Telli, A; Askar, M (2003-05-07) In this study, LNAs for low earth orbit (LEO) S-Band uplink/downlink "System-on-Chip" receiver stages with different topologies are designed and simulated using the Mietec CMOS 0.7mum process and the Cadence/BSIM3v3 tool.

Citation Formats

Y. Başay, “Broadband spectral splitting of light using wavefront shaping,” M.S. - Master of Science, Middle East Technical University, 2018.