Theory of the optimally coupled Q-switched laser

Journal Article · Wed Feb 01 04:00:00 EST 1989 · IEEE J. Quant. Electron.; (United States)

DOI:https://doi.org/10.1109/3.16265· OSTI ID:6218095

Degnan, J J

The general equations describing Q-switched laser operation are transcendental in nature and require numerical solutions. This greatly complicates the optimization of real devices. In this paper, we demonstrate that, using the mathematical technique of Lagrange multipliers, one can derive simple analytic expressions for all of the key parameters of the optimally coupled laser, i.e., one which uses an optimum reflector to obtain maximum laser efficiency for a given pump level. These parameters (which include the optimum reflectivity, output energy, extraction efficiency, pulsewidth, peak power, etc.) can all be expressed as functions of a single dimensionless variable z, defined as the ratio of the unsaturated small-signal gain to the dissipative (non-useful) optical loss, multiplied by a few simple constants. Laser design tradeoff studies and performance projections can be accomplished quickly with the help of several graphs and a simple hand calculator. Sample calculations for a high-gain Nd:YAG and a low-gain alexandrite laser are presented as illustrations of the technique.

• Research Organization: NASA Goddard Space Flight Center, Greenbelt, MD (US)
• OSTI ID: 6218095
• Journal Information: IEEE J. Quant. Electron.; (United States), Journal Name: IEEE J. Quant. Electron.; (United States) Vol. 25:2; ISSN IEJQA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
AMPLIFICATION
CALCULATION METHODS
COUPLING
DATA
GAIN
INFORMATION
LASERS
MATHEMATICAL MODELS
NUMERICAL DATA
NUMERICAL SOLUTION
OPTIMIZATION
PARAMETRIC ANALYSIS
Q-SWITCHING
THEORETICAL DATA