A smoothly tunable 1.432 μmNd:YAlO3 laser was assembled for potential remote sensing of atmospheric CO2 at high altitudes. Continuous laser tuning from 6982.8 to 6984.6 cm−1 was demonstrated, and CO2 absorption lines relatively free of atmospheric water absorption interference at 6983 and 6984 cm−1 were experimentally observed, confirming feasibility of atmospheric CO2 sensing.
We demonstrate a variable pulse width, internally-frequency-converted, near-diffraction-limited Nd:YAG laser with output power up to 40 Watts at 532 nm and pulse widths electronically adjustable over a 40-300 ns range. The variable pulse width is achieved by clipping the pulse decaying edge with the Q-switch in a laser cavity optimized for post-pulse gain insensitivity. This approach makes possible frequency converted lasers with pulse width and output power substantially independent of repetition rate.
Many micromachining operations, particularly in the electronics sector, utilize pulsed solid-state UV lasers. These processes demand high levels of stability, as the yield and quality relate directly to the repeatability of each laser pulse. Critical stability issues arise with single-pulse processes (e.g. repair), situations requiring bursts of pulses (e.g. drilling), and continuous pulsing applications (e.g. cutting). To realize optimal stability specific design choices must be made, certain transient problems must be solved, and pulse energy measurements must be standardized. Solid-state UV lasers originate as infrared lasers, and nonlinear optics converts the infrared to the UV. This conversion introduces instability. Performing the conversion within the infrared laser cavity suppresses the instability, relative to performing the conversion outside of the laser cavity. We explain this phenomenon. Ideally, a versatile and stable solid-state laser can generate pulses in many formats. Thermal effects tend to prevent this versatile ideal, resulting in transient problems (unstable pulse trains), or less than optimal performance when the laser is pulsing continuously. Many methods of measuring pulse energy exist. Each method can produce surprisingly different results. We compare various techniques, discuss their limitations, and suggest an easily implemented pulse energy stability measurement.
The trend in micro-machining lasers is toward greater average power and higher repetition rate, in order to increase throughput, with pulse energy and peak power held roughly constant, as determined by the small scale of the feature. At repetition rates beyond 500 kHz, conventional high-power Q-switched Nd lasers will reach fundamental limits. We demonstrated a fiber-based oscillator-amplifier architecture which produces pulse repetition rates in the 0.5 - 5 MHz range and pulse durations in the 0.5 - 1.5 nsec range. The oscillator is a compact (35 cm<sup>3</sup> package) passively Q-switched Nd:YVO<sub>4</sub> laser oscillating at a single frequency. By amplifying this laser in fiber, we demonstrated 10-W average power at the two wavelengths of 914 nm and 1064 nm. At 1064-nm, Yb-doped large mode area fiber will allow scaling of average power to over 100 Watts, with peak power of tens of kW, in a diffraction-limited beam. Excellent conversion will be possible to visible and UV using the robust nonlinear material LBO. By opening up a new range of repetition rates and pulse lengths, at IR, visible and UV wavelengths, in a high power design that has the packaging and efficiency advantages of fiber, new micro-machining applications may be enabled.
Conference Committee Involvement (2)
Solid State Lasers XVII: Technology and Devices
20 January 2008 | San Jose, California, United States
Solid State Lasers XVI: Technology and Devices
22 January 2007 | San Jose, California, United States
SC1174: Improving Laser Reliability: an Introduction
From science to so-called secret sauces, we will share some of the tricks, techniques, and good practices that go into designing and manufacturing reliable lasers and systems. Lasers are often expensive. Eliminating laser failures, even one laser failure, is a big win. This course examines both optical and non-optical issues that affect reliability. We will emphasize solid-state lasers, frequency-converted lasers, aspects of fiber lasers, and systems that use lasers. We will cover semiconductor lasers, mainly from the perspective of using them as components. Our goal is to help you make more reliable lasers and more reliable laser systems. Together, we will discuss many examples illustrating key failure modes and how to avoid failures. This course has new examples and information for 2018.