Laser-related properties of chromium- and neodymium-doped gadolinium scandium aluminum garnet (Cr:Nd:GSAG)

Journal Article · Sat Oct 01 04:00:00 EDT 1994 · Journal of the Optical Society of America, Part B: Optical Physics; (United States)

DOI:https://doi.org/10.1364/JOSAB.11.002066· OSTI ID:6730352

Sumida, D S; Mangir, M S; Rockwell, D A ^[1]; Shinn, M D ^[2]

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1. Hughes Research Laboratories, 3011 Malibu Canyon Road, M/S RL 65, Malibu, California 90265-4799 (United States)
2. Bryn Mawr College, Department of Physics, Bryn Mawr, Pennsylvania 19010-2899 (United States)

The spectroscopic, lasing, and thermal properties of chromium- and neodymium-doped gadolinium scandium aluminum garnet (Cr:Nd:GSAG) are reported. The Judd--Ofelt parameters, radiative lifetime, and branching ratios were determined, and an effective emission cross-section value of 0.92 [times] 10[sup [minus]19][ital cm][sup 2] was derived at 1.06 [mu]m from our spectroscopic measurements. The temporal behavior of the Cr[sup 3+] fluorescence intensity agreed with the Inokuti--Hirayama model for the chromium--neodymium energy-transfer mechanism, which invokes a static dipole--dipole interaction and no migrational energy transfer. Under identical flash-lamp-pumping conditions the measured pumping efficiency of Cr:Nd:GSAG for threshold lasing is nearly equal to the pumping efficiency of codoped gadolinium scandium gallium garnet (Cr:Nd:GSGG). From the threshold-lasing data, an effective emission cross section of 0.7 [times] 10[sup [minus]19] cm[sup 2] for Cr:Nd:GSAG was independently determined, as well as a value of 1.3 [times] 10[sup [minus]19] cm[sup 2] for Cr:Nd:GSGG. The normalized heating parameter [chi], defined as the heat deposited per unit stored energy, experimentally ranges from 2.1 to 2.7, depending on the effective emission cross-section value. Our calculated value of [chi] is 1.9 [plus minus] 0.3. Based on our heating-efficiency measurements, calculated Cr:Nd:GSAG thermal lensing values are [similar to] 2.1--2.6 D/kW, which indicates a thermally induced focal length that is weaker than that of Nd:YAG by approximately a factor of 2 at the same output power. Finally, the benefits and trade-offs of laser-diode pumping are discussed.

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6730352
• Journal Information: Journal of the Optical Society of America, Part B: Optical Physics; (United States), Journal Name: Journal of the Optical Society of America, Part B: Optical Physics; (United States) Vol. 11:10; ISSN JOBPDE; ISSN 0740-3224
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426002* -- Engineering-- Lasers & Masers-- (1990-)
ABSORPTION SPECTRA
ALLOYS
ALUMINIUM COMPOUNDS
AMPLIFICATION
CHROMIUM ADDITIONS
CHROMIUM ALLOYS
EFFICIENCY
EMISSION
ENERGY-LEVEL TRANSITIONS
GADOLINIUM COMPOUNDS
GAIN
HEATING
LASER MATERIALS
MATERIALS
NEODYMIUM ADDITIONS
NEODYMIUM ALLOYS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RARE EARTH ADDITIONS
RARE EARTH ALLOYS
RARE EARTH COMPOUNDS
SCANDIUM COMPOUNDS
SPECTRA
STIMULATED EMISSION
TRANSITION ELEMENT COMPOUNDS