rahul bhatt - Academia.edu (original) (raw)
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Papers by rahul bhatt
IOP Conference Series: Materials Science and Engineering, 2019
Reflecting Optics is a critical component of any High Power Laser (HPL) based System. With the ad... more Reflecting Optics is a critical component of any High Power Laser (HPL) based System. With the advancements in Laser Sources, power is continuously increasing with decrease in operating wavelength. This has lead toeven more sophisticated upto mechanical design of HPL optics. A large portion of the incident power is reflected and the rest is absorbed and transmitted in various stages. This absorbed power is very detrimental which affects the system performance and may even lead to catastrophic system failure. The mechanism of laser reflection, absorption and transmission is explained in a simple way. General requirements and desired properties of substrate materials are listed. Various metallic and non metallic substrate materials are tabulated along with their physical and mechanical properties. The materials are compared on the basis of their Figure of Merit (ratio of thermal conductivity to coefficient of thermal expansion) andstrength to weight ratio (E/ρ). Finally thermo structu...
Applied optics, 2009
The process of Zernike mode detection with a Shack-Hartmann wavefront sensor is computationally e... more The process of Zernike mode detection with a Shack-Hartmann wavefront sensor is computationally extensive. A holographic modal wavefront sensor has therefore evolved to process the data optically by use of the concept of equal and opposite phase bias. Recently, a multiplexed computer-generated hologram (CGH) technique was developed in which the output is in the form of bright dots that specify the presence and strength of a specific Zernike mode. We propose a wavefront sensor using the concept of phase biasing in the latter technique such that the output is a pair of bright dots for each mode to be sensed. A normalized difference signal between the intensities of the two dots is proportional to the amplitude of the sensed Zernike mode. In our method the number of holograms to be multiplexed is decreased, thereby reducing the modal cross talk significantly. We validated the proposed method through simulation studies for several cases. The simulation results demonstrate simultaneous wavefront detection of lower-order Zernike modes with a resolution better than λ=50 for the wide measurement range of AE3:5λ with much reduced cross talk at high speed.
IOP Conference Series: Materials Science and Engineering, 2019
Reflecting Optics is a critical component of any High Power Laser (HPL) based System. With the ad... more Reflecting Optics is a critical component of any High Power Laser (HPL) based System. With the advancements in Laser Sources, power is continuously increasing with decrease in operating wavelength. This has lead toeven more sophisticated upto mechanical design of HPL optics. A large portion of the incident power is reflected and the rest is absorbed and transmitted in various stages. This absorbed power is very detrimental which affects the system performance and may even lead to catastrophic system failure. The mechanism of laser reflection, absorption and transmission is explained in a simple way. General requirements and desired properties of substrate materials are listed. Various metallic and non metallic substrate materials are tabulated along with their physical and mechanical properties. The materials are compared on the basis of their Figure of Merit (ratio of thermal conductivity to coefficient of thermal expansion) andstrength to weight ratio (E/ρ). Finally thermo structu...
Applied optics, 2009
The process of Zernike mode detection with a Shack-Hartmann wavefront sensor is computationally e... more The process of Zernike mode detection with a Shack-Hartmann wavefront sensor is computationally extensive. A holographic modal wavefront sensor has therefore evolved to process the data optically by use of the concept of equal and opposite phase bias. Recently, a multiplexed computer-generated hologram (CGH) technique was developed in which the output is in the form of bright dots that specify the presence and strength of a specific Zernike mode. We propose a wavefront sensor using the concept of phase biasing in the latter technique such that the output is a pair of bright dots for each mode to be sensed. A normalized difference signal between the intensities of the two dots is proportional to the amplitude of the sensed Zernike mode. In our method the number of holograms to be multiplexed is decreased, thereby reducing the modal cross talk significantly. We validated the proposed method through simulation studies for several cases. The simulation results demonstrate simultaneous wavefront detection of lower-order Zernike modes with a resolution better than λ=50 for the wide measurement range of AE3:5λ with much reduced cross talk at high speed.