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87 results on '"Lenzner, Matthias"'

2. Impact of giant resonant dispersion on the response of intracavity phase interferometry and laser gyros

Author

Hendrie, James, Lenzner, Matthias, Diels, Jean Claude, and Arissian, Ladan

Subjects
Physics - Optics
Abstract

Intracavity Phase Interferometry is a phase sensing technique using mode-locked lasers in which two intracavity pulses circulate. The beat frequency between the two output frequency combs is proportional to a phase shift to be measured. A laser gyro is a particular implementation of this device. The demonstrated sensitivity of $10^{-8}$ could be manipulated by applying a giant dispersion to each tooth of the comb. Such coupling is achieved with an intracavity etalon, resulting a large change in phase response of a ring laser. This change is shown to be unrelated to the average pulse velocity within the laser cavity., Comment: 10 pages,5 figures

Published
2016
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11. Phase Nanoscopy with Correlated Frequency Combs.

Author

Zhu, Xiaobing, Lenzner, Matthias, and Diels, Jean-Claude

Subjects
*OPTICAL parametric oscillators, *FEMTOSECOND pulses, *MODE-locked lasers, *LASER pumping, *LITHIUM niobate, *STANDARD deviations, *PULSE generators
Abstract

This study addresses any sensor based on measuring a physical quantity through the phase of a probing beam. This includes sensing of rotation, acceleration, index change, displacement, fields... While most phase measurements are made by detecting an amplitude change in interfering beams, we detect instead a phase change through a relative frequency shift of two correlated frequency combs. This paper explores the limit sensitivity that this method can achieve, when the combs are generated in an Optical Parametric Oscillator (OPO), pumped synchronously by a train of femtosecond pulses separated by half the OPO cavity round-trip time. It is shown that a phase difference as small as 0.4 nanoradians can be resolved between the two pulses circulating in the cavity. This phase difference is one order of magnitude better than the previous record. The root-mean-square deviation of the measured phase over measuring time is close to the standard quantum limit (phase-photon number uncertainty product of 0.66). Innovations that made such improved performances possible include a more stable OPO cavity design; a stabilization system with a novel purely electronic locking of the OPO cavity length relative to that of the pump laser; a shorter pump laser cavity; and a square pulse generator for driving a 0.5 mm pathlength lithium niobate phase modulator. Future data acquisition improvements are suggested that will bring the phase sensitivity exactly to the standard quantum limit, and beyond the quantum limit by squeezing. [ABSTRACT FROM AUTHOR]

Published
2023
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16. Generic incubation law for laser damage and ablation thresholds.

Author

Zhanliang Sun, Lenzner, Matthias, and Rudolph, Wolfgang

Subjects
*LASER damage, *ABLATION (Aerothermodynamics), *DIELECTRIC devices, *METALS, *LIGHT emitting diodes
Abstract

In multi-pulse laser damage and ablation experiments, the laser-induced damage threshold (LIDT) usually changes with the number of pulses in the train, a phenomenon known as incubation. We introduce a general incubation model based on two physical mechanisms-pulse induced change of (i) absorption and (ii) critical energy that must be deposited to cause ablation. The model is applicable to a broad class of materials and we apply it to fit data for dielectrics and metals. It also explains observed changes of the LIDT as a function of the laser repetition rate. We discuss under which conditions the crater-size method to determine LIDTs can be applied in multi-pulse experiments. [ABSTRACT FROM AUTHOR]

Published
2015
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27. Sub-nanosecond UV filaments and their applications for remote spectroscopy and high-voltage discharges

Author

Diels, Jean-Claude, Arissian, Ladan, Krishna, Sanjay, Lenzner, Matthias, Feng, Chengyong, Diels, Jean-Claude, Arissian, Ladan, Krishna, Sanjay, Lenzner, Matthias, and Feng, Chengyong

Abstract

Intensive investigations during the past two decades have focused on potential applications of near-infrared (NIR) femtosecond filament for remote spectroscopy. The short length (less than 1 m) and low energy (only several millijoule) of a single NIR filament limit these applications. Long-pulse UV filaments have therefore been proposed at UNM to overcome such limitations. This dissertation describes our investigation and optimization of the high-power UV source, focusing on details of the generation and characterization of the generated pulses, as well as the applications of UV filaments for remote sensing and high-voltage discharge. On the topic of pulse generation, a 266 nm UV system delivering laser pulses below 200 ps with up to 0.4 J per pulse at 1.25 Hz repetition rate is developed. Two aspects of the laser source are closely investigated. On the one hand, the spatio-temporal profile of the laser pulses that has been overlooked for decades is systematically studied. It is shown that a curved energy front, i.e., pulses away from the beam center delayed from the center pulse, originates from the Q-switched unstable cavity Nd:YAG oscillator and evolves during the processes of laser amplification and pulse compression. To eliminate the energy front curvature, a possible solution is proposed based on the numerical simulation. On the other hand, a long existing debate on the minimum pulse duration that can be achieved through stimulated Brillouin scattering (SBS) pulse compression is resolved by this work. It is demonstrated that the lower limit of the compressed pulse duration is not set by the phonon lifetime of the SBS medium. The energy exchange between the pump and compressed Stokes pulses is responsible for the pulse compression below phonon lifetime. Next, using the newly developed powerful and stable UV source, the generation of UV filaments in air is studied. It is shown that, when focused by a 3 m lens, a single filament is generated inside the laboratory

Published
2016

30. High-resolution remote spectroscopy and plasma dynamics induced with UV filaments

Author

Rastegari, Ali, Lenzner, Matthias, Diels, Jean-Claude, Peterson, Kristen, and Arissian, Ladan

Abstract

Spectroscopy is performed on the plume created by a high-power short-pulse laser on a solid surface. It is shown that high resolution (<10  pm) and accurate spectral analysis can be performed using a self-absorption feature appearing within the emission lines. The time-dependent self-absorption study reveals dynamics of a shock wave.

Published
2019

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