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Publication Date

Spring 2021

Degree Type

Thesis - Campus Access Only

Degree Name

Master of Science (MS)

Department

Physics

Advisor

Peter Beyersdorf

Keywords

Etching, Gain, Laser, Nd:YVO4, Simulation

Subject Areas

Optics

Abstract

We simulated the gain dynamics of neodymium-doped yttrium orthovanadate (Nd:YVO$_{4}$) crystal by creating a diode-pumped solid state laser in Python, with a pulsed Nd:YAG laser as the seed beam, and an 808 $nm$ laser diode for the pump. This was used to examine how the gain dynamics of Nd:YVO$_{4}$ change with delay time between pulses. These results are presented in the context of laser etching, where a single pulse is used to ablate an entire image into a material. We look at how the spatial crosstalk between etchings with different spatial profiles, combined with delay time, affects gain extraction across the crystal. We relate these findings to barcode etchings, and observe how different combinations of spatial crosstalk and delay time affect the potential write rate for laser etchings as well as the resulting etch depth uniformity from each pulse. We found that etchings with spatial profiles containing spatial crosstalk could be produced with a sufficiently long pulse delay time, which limits the write rate. We also found that higher write rates could be achieved if consecutive images lacked spatial correlation. We also discuss methods to improve uniformity when spatial crosstalk is present, and model how spatial crosstalk and uniformity affect maximum write rate. We found that barcode pairs with an RMS deviation of 0.7 produce the worst uniformity when pulsed in succession, and as the RMS deviation between barcodes increases or decreases from this point etching uniformity improves.

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