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Results for “Diode-pumped Laser”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Frequency noise measurement of diode-pumped Nd:YAG ring lasers

The combined frequency noise spectrum of two model 120-01A nonplanar ring oscillator lasers was measured by first heterodyne detecting the IF signal and then measuring the IF frequency noise using an RF frequency discriminator. The results indicated the presence of a 1/f-squared noise component in the power-spectral density of the frequency fluctuations between 1 Hz and 1 kHz. After incorporating this 1/f-squared into the analysis of the optical phase tracking loop, the measured phase error variance closely matches the theoretical predictions.

Chen, Chien-Chung↗
NASA NTRS1991

High-power pulsed and CW diode-pumped mode-locked Nd:YAG lasers

The operation of both pulsed and CW diode-pumped mode-locked Nd:YAG lasers are presented. The pulsed laser produced 1.0 mJ with pulsewidths of 90 psec at 20 Hz. The CW pumped laser produced 6 W output at 1.064 microns and 3 W output at 532 nm.

Marshall, Larry R.↗
NASA NTRS1985

Tunable solid state lasers for remote sensing; Proceedings of the Conference, Stanford University, CA, October 1-3, 1984

Papers are presented on solid-state lasers for remote sensing, diode-pumped Nd:YAG lasers, and tunable solid-state-laser systems. Topics discussed include titanium-sapphire tunable laser systems, the performance of slab geometry, and the development of slab lasers. Consideration is given to garnet host solid-state lasers, the growth of lasers and nonlinear materials, and nonlinear frequency conversion and tunable sources.

Byer, R. L.↗
NASA NTRS1990

Intensity noise in diode-pumped single-frequency Nd:YAG lasers and its control by electronic feedback

The power spectrum of the relative intensity noise (RIN) of single-frequency diode-pumped Nd:YAG lasers is observed to be shot-noise limited at frequencies above 20 MHz for a photocurrent of up to 4.4 mA. Relaxation oscillations result in noise 60-70 dB above shot noise at a few hundred kHz. These relaxation oscillations have been suppressed using electronic feedback.

Kane, Thomas J.↗
NASA NTRS1985

Nd:YAG end pumped by semiconductor laser arrays for free space optical communications

Preliminary experimental results are reported for a diode-pumped Nd:YAG laser employing a tightly focused end-pump geometry. The resonator configuration is planoconcave, with the pumped end of the Nd:YAG rod being coated for high reflection at 1.06 microns. This geometry rectifies nearly all the inefficiencies plaguing side-pumped schemes. This laser is further considered as a candidate for optical communication over the deep space channel.

Sipes, D. L., Jr.↗
NASA NTRS1986

Diode-pumped continuous-wave Nd:glass laser

The paper reports on diode-laser pumping of monolithic Nd:glass laser oscillators. End pumping with a single-stripe diode laser, a threshold of 2.2 mW, and a slope efficiency of 42 percent were observed on a 2-mm-long oscillator with a mode radius of 35 microns. The oscillator generated 2.5 mW of single-ended output power in many axial modes.

Kozlovsky, W. J.↗
NASA NTRS1988

Modulation techniques for deep-space pulse-position modulation (PPM) optical communication

The extremely energy-efficient pulse-position modulation (PPM) format is being actively developed as a basis for optical communications with deep-space probes. Attention is presently given to different modulation schemes for the efficient production of laser pulses over a broad range of repetition rates. Both Q-switching and cavity dumping modulation methods are available for the envisioned diode-pumped Nd:YAG laser source. Numerical calculation results are presented for cavity-dumping.

Rayman, Marc D.↗
NASA NTRS1988

Diode laser-pumped solid-state lasers

Recently, interest in diode laser-pumped solid-state lasers has increased due to their advantages over flashlamp-pumped solid-state lasers. A historical overview is presented of semiconductor diode-pumped solid-state lasers beginning with work in the early 1960s and continuing through recent work on wavelength extension of these devices by laser operation on new transitions. Modeling of these devices by rate equations to obtain expressions for threshold, slope efficiency, and figures of merit is also given.

Fan, Tso Yee↗
NASA NTRS1988

Lunar observer laser altimeter

Understanding the global topography of the Moon is especially important for answering questions concerning lunar origin and evolution. Many outstanding problems in lunar science can be addressed with high resolution topographic data. The severe power, mass, size, and data-rate limitations imposed by the Lunar Geoscience Observer (LGO) and other Observer-class missions are major challenges for all instruments capable of measuring topography. A radar altimeter that meets these strict requirements could obtain a global prespective of lunar topography with a few kilometers spatial resolution and 10 m vertical resolution from a lunar orbit of 100 km. A prototype model is being constructed of the Lunar Observer Laser Altimeter (LOLA) capable of continuously measuring the range to the lunar surface with sub-meter vertical resolution within a 30 to 300 m diameter surface footprint. This same instrument is also designed to provide a direct measure of the surface height distribution in the footprint by waveform analysis of the backscattered laser pulse. Both these measurements are to be made in a continuous, nadir profile across the lunar surface from a 100 km orbit. The wavelength of the altimeter is 1064 nm. A short-pulse (2 nsec), diode-pumped Nd:YAG laser combined with a 25 cm diameter telescope, silicon avalanche photodiode detector, ranging electronics, and instrument computer was designed to make these measurements and meet all the requirements of the LGO mission.

Bufton, J. L.↗
NASA NTRS1991

Efficient energy extraction from a diode-pumped Q-switched Tm,Ho:YLiF4 laser

The operation of a diode-laser pumped thulium, holmium yttrium-lithium-fluoride laser (Tm,Ho:YLF) in Q-switched mode is reported. Output energies of 200 microjoules in pulses of 22 ns duration are recorded at Q-switch frequencies commensurate with an effective upper laser level lifetime of 6 ms. This lifetime is appreciably longer than that observed in other hosts permitting stored energy extraction of 64 percent, close to the projected maximum performance from these materials.

Mcguckin, B. T.↗
NASA NTRS1989

Laser altimetry measurements from aircraft and spacecraft

The techniques involved in the design and application of laser altimeter instruments are reviewed, including a description of the instrument subsystems required for the range and waveform measurements. Laser pulse transmitters based on the relatively novel technology of diode-pumped solid-state lasers are considered. Various factors affecting laser altimeter instrument performance are discussed. These include the receiver signal-to-noise ratio, atmospheric propagation, and altimeter platform effects. Some examples of laser altimeter data are presented to illustrate the variety of possible instrument applications.

Bufton, Jack L.↗
NASA NTRS1991

High-resolution measurements of surface topography with airborne laser altimetry and the global positioning system

Recently, an airborne lidar system that measures laser pulse time-of-flight and the distortion of the pulse waveform upon reflection from earth surface terrain features was developed and is now operational. This instrument is combined with Global Positioning System (GPS) receivers and a two-axis gyroscope for accurate recovery of aircraft position and pointing attitude. The laser altimeter system is mounted on a high-altitude aircraft platform and operated in a repetitively-pulsed mode for measurements of surface elevation profiles at nadir. The laser transmitter makes use of recently developed short-pulse diode-pumped solid-state laser technology in Q-switched Nd:YAG operating at its fundamental wavelength of 1064 nm. A reflector telescope and silicon avalanche photodiode are the basis of the optical receiver. A high-speed time-interval unit and a separate high-bandwidth waveform digitizer under microcomputer control are used to process the backscattered pulses for measurements of terrain. Other aspects of the lidar system are briefly discussed.

Garvin, James B.↗
NASA NTRS1991

Airborne lidar for profiling of surface topography

A lidar system is described that measures laser pulse time-of-flight and the distortion of the pulse waveform for reflection from earth surface terrain features. This instrument system is mounted on a high-altitude aircraft platform and operated in a repetitively pulsed mode for measurements of surface elevation profiles. The laser transmitter makes use of recently developed short-pulse diode-pumped solid-state laser technology. Aircraft position in three dimensions is measured to submeter accuracy by use of differential Global Positioning System receivers. Instrument construction and performance are detailed.

Bufton, Jack L.↗
NASA NTRS1985

Conducting a wind sensing study

Signal-to-noise requirements, and how signal-to-noise determines wind velocity measurement accuracy were studied. A Nd:YAG-based system was found to be competitive with a CO2-based system. Hardware was developed for a coherent Nd:YAG LIDAR system, and is being integrated into a functioning system. A diode-pumped monolithic rod laser to be used as a reference oscillator, a high-power, single-mode ring laser, for use as a master oscillator, and a high-gain, multipass amplifier were constructed.

Byer, R. L.↗
NASA NTRS1989

Optical communications systems and technology for deep-space exploration

An account is given of architectural and implementational strategies for the creation of planetary and other deep-space optical communications networks, with a view to the developmental requirements of both planetary spacecraft subsystems and an earth-vicinity reception system. Attention is given to prospective technology-development challenges. An open-loop spatial acquisition process is defined, in conjunction with a terrestrial, large-aperture/low-cost 'photon bucket' optical reception telescopic system having an integral, axially-aligned tube-bundle sunshield. An efficient diode-pumped Nd:YAG laser is envisioned as the transmitter.

Lesh, James R.↗
NASA NTRS1992

Analytic Solutions Of Equations For Q-Switched Lasers

Approximate closed-form, analytic equations for characteristics of Q-switched, continuous-wave-pumped laser express relationships among characteristics of output, pumping rate above threshold pumping rate, and rate of repetition of switch. Equations describe performance in terms of peak output power, energy in each pulse, average output power, and duration of each pulse as functions of pulse-repetition rate, actual pump power, threshold pump power, volume occupied by laser electromagnetic mode, and reflectivity of output coupler. Useful for analyzing performances of diode-pumped solid-state lasers.

Wilson, Keith E.↗
NASA NTRS1991

Efficient second-harmonic conversion of CW single-frequency Nd:YAG laser light by frequency locking to a monolithic ring frequency doubler

Efficient second-harmonic conversion of the 1064-nm output of a diode-pumped CW single-frequency Nd:YAG laser to 532 nm was obtained by frequency locking the laser to a monolithic ring resonator constructed of magnesium-oxide-doped lithium niobate. The conversion efficiency from the fundamental to the second harmonic was 65 percent. Two hundred milliwatts of CW single-frequency 532-nm light were produced from 310 mW of power of 1064-nm light. This represents a conversion efficiency of 20 percent from the 1-W diode laser used to pump the Nd:YAG laser to single-frequency 532-nm output. No signs of degradation were observed for over 500 h of operation.

Gerstenberger, D. C.↗