YCOB -a new nonlinear optical crystal for high average power, efficient, visible wavelength , solid-state laser sources.

Laser Energetics Inc. will exploit the recent development of a new nonlinear optical crystal, YCa4O(BO3)3 (YCOB), to provide high average power visible laser radiation by harmonic conversion. This crystal has a number of advantages over other commonlyavailable nonlinear optical crystals. It has a higher or equal magnitude of nonlinear coefficient than crystals such as KDP, LBO, or BBO and yet it is non-hygroscopic. It has good optical and thermo-mechanical properties, a high optical damage thresholdand, unlike KTP, can be grown rapidly to large sizes of over 3 inches in diameter and 10 inches in length in approximately 1 week. Moreover, because it's short-wavelength transmission cut-off is well into the UV, it does not suffer from the photochromicdiscoloration phenomena that occurs in other non-linear optical crystals (such as KTP or LiNBO3) that have high nonlinear coefficients. In the Phase I project we will make a thorough characterization of the thermo-mechanical properties of YCOB (it'snonlinear optical properties have already been characterized by the Richardson group). We will also make high average optical power (>300W) loading tests, and design the optimum thermal cooling environment for this crystal to be incorporated into asolid-state 100W visible laser system. With the successful development of a high power tunable visible laser source, Laser Energetics will move quickly to bring this technology to bear on the laser materials processing and machining industries. LEI isalready making rapid progress in introducing laser processing techniques to replace other less accurate, more cumbersome technologies, in the computer and micro-electronics industries, in the marking industry, in some biotech companies, and in a variety ofspecialized micro processing applications. Laser Energetics Inc. (LEI) is in a unique position to pursue the further development of YCOB as a crystal capable of handling high average powers. LEI is the only company in the US at present commercializingYCOB as a laser medium. It sponsored the development at CREOL, now the School of Optics-CREOL, at the University of Central Florida, of Nd-doped YCOB as a new diode-pumped crystalline laser medium, This material has the unique characteristic of being botha solid-state laser medium, and a nonlinear optical medium. The company has now developed this into the first commercial, diode-pumped, self-frequency doubled laser at 530 nm. In this project we will partner with the Richardson group at CREOL, which ledthe early development of YCOB as a laser medium. This is the best possible university partner LEI could wish for in the development un-doped YCOB as a nonlinear optical crystal for high average power laser operation. This group was one of the first torecognize the unique advantages of using YCOB as a nonlinear optical crystal, and has already published several scientific articles on this topic. Moreover the group has access to several high power solid-state laser systems, and at UCF, to an extensivearray of thermo-mechanical and solid-state materials analysis equipment, housed in the UCF AMPAC Materials Characterization Facility (MCF). Laser Energetics will integrate the advances of this proposal directly into the 100+ W level Diode Pumped SolidState tunable lasers that we are currently under development for micro-machining applications.