Timothy Day

Sub-hertz relative frequency stabilization of two-diode laser-pumped Nd:YAG lasers locked to a Fabry-Perot interferometer

Two-diode laser-pumped Nd:YAG lasers have been frequency stabilized to a commercial 6.327-GHz free spectral range Fabry-Perot interferometer yielding a best-case beatnote linewidth of 330 mHz. In addition, a Fabry-Perot interferometer with a free spectral range of 680 MHz, a linewidth of 25 kHz, and a finesse of 27500 has been built, and when substituted in place of the commercial interferometer produced a robust and easily repeatable beatnote linewidth of 700 MHz. >

Coherence properties of a doubly resonant monolithic optical parametric oscillator

We describe a doubly resonant optical parametric oscillator (DRO) pumped with the second harmonic of a narrow-linewidth Nd: YAG laser. The linewidth of the DRO signal was less than 13 kHz, the DRO was shown to generate a phase-locked subharmonic of the pump at degeneracy, and the signal and the idler were shown to be mutually coherent with the pump and to be phase anticorrelated with each other away from degeneracy. The signal–idler heterodyne linewidth was 500 Hz, and pump phase modulation was shown to transfer to the DRO phase at degeneracy.

Injection locking of a 13-W cw Nd:YAG ring laser

A lamp-pumped, 13-W cw Nd:YAG ring laser at 1.064 microm is injection locked using a 40-mW single-frequency diodelaser-pumped Nd:YAG laser as the master oscillator. The phase fidelity of the injected slave to the master is measured using an all-optical technique.

Active frequency stabilization of a 1.062-μm, Nd:GGG, diode-laser-pumped nonplanar ring oscillator to less than 3 Hz of relative linewidth

We present results on the frequency stabilization of two diode-laser-pumped ring lasers that are independently locked to the same high-finesse interferometer. We measure the relative frequency stability by locking the lasers one free spectral range apart and observing the heterodyne beat note. The resultant beat note width of 2.9 Hz is consistent with the theoretical system noise-limited linewidth and is approximately 20 times that expected for shot-noise-limited performance.

Performance characteristics of a continuous-wave compact widely tunable external cavity interband cascade lasers

We present the design and performance of a novel broadly tunable continuous-wave external-cavity interband cascade laser (ECicL). The ICL die growth and fabrication, as well as the external cavity geometry are described. Tuning across the 3.2-3.35 microm wavelength range, limited by the gain width of the ICL active medium, is achieved at a maximum power level of 4 mW.

Demonstration of a low bandwidth 1.06 mu m optical phase-locked loop for coherent homodyne communication

A type-II, 1.06- mu m, optical phase-locked-loop (OPLL) for use in a coherent homodyne receiver is discussed. Diode-laser-pumped solid-state lasers are used for both the local oscillator and transmitter, because their phase noise is significantly lower than that of diode lasers. Closed-loop RMS phase noise of less than 12 mrad (0.69 degrees ) is achieved, and modulation-demodulation in bulk modulators at rates from 20 kHz to 20 MHz with less than 19 degrees of modulation depth is demonstrated.<<ETX>>

Room Temperature CW Operation of Short Wavelength Quantum Cascade Lasers Made of Strain Balanced Ga

We present our recent development of short wavelength quantum cascade lasers (QCLs) made of strain balanced Ga_xIn_1-xAs/Al_yIn_1-yAs material on InP substrates. We demonstrate room temperature continuous-wave (CW) lasing of the fundamental lateral mode at four wavelengths of 4.6, 4.0, 3.8, and 3.5 μm. We obtained 60-mW CW output power at 10 °C and 3.55-μm wavelength, which is the shortest CW lasing wavelength demonstrated at room temperature by a QCL, to the best of our knowledge. We also performed a life test on λ = 4.6 μm QCL chips. To date, we have accumulated the life test data for more than 11 000 and 4100 h under two aging conditions, 20°C and 0.85-A constant current, and 60°C and 1-A constant current, respectively.

_{\bm x}

In this paper, watt-level continuous-wave (CW) output powers at wavelengths longer than 10 μm are demonstrated at room temperature with quantum cascade lasers (QCLs). CW output power of 1.15 W is demonstrated at λ ~ 10.3 μm for a QCL which has a 6-mm-long cavity and a 14-μm-wide stripe. CW output power of 1.3 W is demonstrated at λ ~ 10.7 μm for a QCL which has 6-mm-long cavity and 11.5-μm width, with a CW threshold current of 1.96 kA/cm². Moreover, 1-W kink-free CW output power is demonstrated with a laser with a 9.5-μm-wide stripe. The maximum pulsed and CW wall plug efficiencies reached 10.4% and 4.8%, respectively, for the QCLs with λ ~ 10.7 μm.

In

Daylight Solutions is currently developing field deployable, high power, wavelength agile, external cavity quantum cascade lasers (EC-QCLs). These devices are finding uses as IR sources for applications such as remote gas sensing, imaging, and illumination. Progress in three specific areas of development will be discussed: (i) miniaturization of a fast tunable, moderate resolution, pulsed QCL for gas sensing, (ii) demonstration of high power mod hop free tunable CW QCLs for high resolution spectroscopy, and (iii) progress in development of battery powered high efficiency fixed wavelength EC-QCL light sources for molecular imaging and detection.

_{\bm {1-x}}

A room-temperature, grating-tuned external cavity quantum cascade laser is demonstrated. The use of miniaturized components leads to superior performance (8.3 to 9.0 um tuning) and facilitates the development of a robust commercial module.