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Title: Pyroelectricity and its role in optical damage of potassium titanyl phosphate crystals

Conference ·
OSTI ID:414634

The origin of optical damage in potassium titanyl phosphate (KTP) crystals has been vigorously investigated since its introduction as a nonlinear optical material in 1976. It is well known that this material exhibits a laser damage threshold that limits its use in many high average-power applications, especially frequency doubling of Nd-doped lasers. Both photochromic and electrochromic damage can be induced in KTP. Until recently, it was thought that these two types of damage were distinctly different, possibly involving different mechanisms; however, new data show that electrochromic-like damage can be induced in KT? by laser irradiation only, implying the existence of an internal electric field. We have recently observed bursts of light (optical scintillations) when heating KTP crystals at 0.1 - 1.0 K/s in the temperature range 8 - 675 K. The scintillations correspond to molecular nitrogen emission occurring during the electrical breakdown of air near the crystal surface, and imply the existence of pyroelectric fields in KTP exceeding 30 kV/cm. These fields (and concomitant currents) were induced by 10.6 {mu}m laser irradiation. The observation of pyroelectric effects, heretofore not considered in KTP damage models, provides an important new insight into the possible cause of the recently observed {open_quotes}electrochromic-like{close_quotes} photochromic damage in KTP.

Research Organization:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Assistant Secretary for Human Resources and Administration, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
414634
Report Number(s):
LA-UR-96-3605; CONF-961070-2; ON: DE97001719; TRN: 97:000090
Resource Relation:
Conference: 28. annual symposium on optical materials for high power lasers - Boulder damage symposium, Boulder, CO (United States), 7-9 Oct 1996; Other Information: PBD: 1996
Country of Publication:
United States
Language:
English