Spectral Characteristics of Thick Phase Holographic Gratings

Recording and analysis of off-axis multiplexed volume holographic lens for wavelength selective wide acceptance angle operation in concentrator photovoltaics

“…The VHOES as dispersive concentrating systems find their use in a spectral splitting photovoltaic system for solar cells of matched bandgaps 13 – 18 Researchers throughout the world have investigated different features of holographic optical elements as a photovoltaic concentrator due to their cost effectiveness and ease of mass production through replication 8 – 12 , 15 – 43 …”

“… – 18 Researchers throughout the world have investigated different features of holographic optical elements as a photovoltaic concentrator due to their cost effectiveness and ease of mass production through replication 8 – 12 , 15 – 43 …”

“…It has been shown that a properly designed off-axis volume holographic lens can provide wavelength-selective performance 12 , 15 – 17 , 19 The wavelength selectivity of a thick phase hologram shows the range of wavelengths that can pass through the hologram with appreciable diffraction efficiency for the on-Bragg angle of reconstruction. This is determined from the spectral characteristics curves drawn for the hologram for different optimized values of processing parameters, namely film thickness (d), fringe spacing (Λ), and depth of refractive index modulation (Δn).…”

“…This is determined from the spectral characteristics curves drawn for the hologram for different optimized values of processing parameters, namely film thickness (d), fringe spacing (Λ), and depth of refractive index modulation (Δn). Spectral characteristic curves of a hologram show the variation of diffraction efficiency with wavelength for the on-Bragg angle of reconstruction 17 . Further, with the aid of theoretically computed design curves, as shown in Fig.…”

“…Spectral characteristic curves of a hologram show the variation of diffraction efficiency with wavelength for the on-Bragg angle of reconstruction. 17 Further, with the aid of theoretically computed design curves, as shown in Fig. 2(a), it is seen that the change in the spectral characteristics curves for a volume holographic lens with the change in fringe spacing (Λ) recorded in the hologram does not affect the diffraction efficiency significantly over the spectral range 450 to 600 μm for on Bragg angle illumination, however, the processing parameters may suitably be designed to obtain high diffraction efficiency over the desired spectral range for different kind of solar cells.…”