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14 pages, 2388 KiB

Open AccessArticle

Performance Evaluation of Solid-State Laser Gain Module by Measurement of Thermal Effect and Energy Storage

by Daewoong Park, Jihoon Jeong, Seungjin Hwang, Sungyoon Lee, Seryeyohan Cho and Tae Jun Yu

Photonics 2021, 8(10), 418; https://doi.org/10.3390/photonics8100418 - 29 Sep 2021

Cited by 3 | Viewed by 2917

Abstract

The optimization of solid-state laser cavities requires a deep understanding of the gain module, the most critical laser component. This study proposes a procedure for evaluating the performance of the solid-state laser gain module. The thermal effect and energy storage characteristics are the [...] Read more.

The optimization of solid-state laser cavities requires a deep understanding of the gain module, the most critical laser component. This study proposes a procedure for evaluating the performance of the solid-state laser gain module. The thermal effect and energy storage characteristics are the performance criteria. A normalized heating parameter was calculated as a quantitative indicator of the performance criteria. We proposed a method to quantify the heat dissipated into the gain medium using the wavefront distortion, thermal deformation theory of the gain medium, and the ray transfer matrix method. The suggested procedure was verified by evaluating the flashlamp type Nd:YAG rod gain module, but it can also even be extended to other solid-state laser gain modules by applying the appropriate thermal deformation theory. Full article

(This article belongs to the Special Issue Laser Amplifiers)

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10 pages, 4106 KiB

Open AccessCommunication

Development of a 1 TW/35 fs Ti:sapphire Laser Amplifier and Generation of Intense THz Waves Using Two-Color Laser Filamentation

by Vanessa Ling Jen Phung, Keekon Kang, Seongjin Jeon, Jinju Kim, Kyungmin Roh and Hyyong Suk

Photonics 2021, 8(8), 316; https://doi.org/10.3390/photonics8080316 - 5 Aug 2021

Cited by 2 | Viewed by 3373

Abstract

We developed a compact Ti:sapphire laser amplifier system in our laboratory, generating intense laser pulses with a peak power of >1 TW (terawatt), a pulse duration of 34 fs (femtosecond), a central wavelength of 800 nm, and a repetition rate of 10 Hz. [...] Read more.

We developed a compact Ti:sapphire laser amplifier system in our laboratory, generating intense laser pulses with a peak power of >1 TW (terawatt), a pulse duration of 34 fs (femtosecond), a central wavelength of 800 nm, and a repetition rate of 10 Hz. The laser amplifier system consists of a mode-locked Ti:sapphire oscillator, a regenerative amplifier, and a single-side-pumped 4-pass amplifier. The chirped-pulse amplification (CPA)-based laser amplifier was found to provide an energy of 49.6 mJ after compression by gratings in air, where the pumping fluence of 1.88 J/cm² was used. The amplified spontaneous emission (ASE) level was measured to be lower than 10⁻⁷, and ps-prepulses were in 10⁻⁴ or lower level. The developed laser amplifier system was used for the generation of intense THz (terahertz) waves by focusing the original (800 nm) and second harmonic (400 nm) laser pulses in air. The THz pulse energy was shown to be saturated in the high laser energy regime, and this phenomenon was confirmed by fully electromagnetic, relativistic, and self-consistent particle-in-cell (PIC) simulations. Full article

(This article belongs to the Special Issue Laser Amplifiers)

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8 pages, 2607 KiB

Open AccessCommunication

Phase Compensation Method in OPA System Based on the Linear Electro-Optic Effect

by Shuaishuai Yang and Dean Liu

Photonics 2021, 8(4), 126; https://doi.org/10.3390/photonics8040126 - 17 Apr 2021

Cited by 3 | Viewed by 2276

Abstract

Factors such as mechanical deformation and temperature changes lead to phase mismatch in optical parametric amplification systems, impacting energy stability. A phase compensation method via the linear electro-optic effect can overcome this limitation. Phase mismatch compensation characteristics were simulated via the linear electro-optic [...] Read more.

Factors such as mechanical deformation and temperature changes lead to phase mismatch in optical parametric amplification systems, impacting energy stability. A phase compensation method via the linear electro-optic effect can overcome this limitation. Phase mismatch compensation characteristics were simulated via the linear electro-optic effect in 70%-deuterated DKDP and 95%-deuterated DKDP. This method was applied to OPA systems to verify its feasibility. The results show that the temperature acceptance bandwidth of 70%-deuterated DKDP and 95%-deuterated DKDP can be ~1.75 and ~2 times larger, respectively, than that of the OPA without compensation. Moreover, the angle acceptance bandwidth of 70%-deuterated DKDP and 95%-deuterated DKDP can be ~2 times larger than that of the OPA without compensation. The abovementioned method can facilitate the compensation of phase mismatch within a range and can be widely used in OPA and optical parametric chirped pulse amplification systems to improve laser stability. Full article

(This article belongs to the Special Issue Laser Amplifiers)

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13 pages, 629 KiB

Open AccessFeature PaperArticle

High-Peak-Power Long-Wave Infrared Lasers with CO₂ Amplifiers

by Mikhail N. Polyanskiy, Igor V. Pogorelsky, Marcus Babzien, Rotem Kupfer, Navid Vafaei-Najafabadi and Mark A. Palmer

Photonics 2021, 8(4), 101; https://doi.org/10.3390/photonics8040101 - 31 Mar 2021

Cited by 27 | Viewed by 4469

Abstract

Long-wave infrared (LWIR) picosecond pulses with multi-terawatt peak power have recently become available for advanced high-energy physics and material research. Multi-joule pulse energy is achieved in an LWIR laser system via amplification of a microjoule seed pulse with high-pressure, mixed-isotope CO

_{2}

amplifiers. [...] Read more.

Long-wave infrared (LWIR) picosecond pulses with multi-terawatt peak power have recently become available for advanced high-energy physics and material research. Multi-joule pulse energy is achieved in an LWIR laser system via amplification of a microjoule seed pulse with high-pressure, mixed-isotope CO

_{2}

amplifiers. A chirped-pulse amplification (CPA) scheme is employed in such a laser to reduce the nonlinear interaction between the optical field and the transmissive elements of the system. Presently, a research and development effort is underway towards an even higher LWIR peak power that is required, for instance, for promising particle acceleration schemes. The required boost of the peak power can be achieved by reducing the pulse duration to fractions of a picosecond. For this purpose, the possibility of reducing the gain narrowing in the laser amplifiers and post-compression techniques are being studied. Another direction in research is aimed at the increased throughput (i.e., repetition rate), efficiency, and reliability of LWIR laser systems. The transition from a traditional electric-discharge pumping to an optical pumping scheme for CO

_{2}

amplifiers is expected to improve the robustness of high-peak-power LWIR lasers, making them suitable for broad implementation in scientific laboratory, industrial, and clinical environments. Full article

(This article belongs to the Special Issue Laser Amplifiers)

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13 pages, 6772 KiB

Open AccessArticle

Modeling and Measurement of Thermal Effect in a Flashlamp-Pumped Direct-Liquid-Cooled Split-Disk Nd:LuAG Ceramic Laser Amplifier

by Shengzhe Ji, Wenfa Huang, Tao Feng, Long Pan, Jiangfeng Wang, Xinghua Lu, Benxue Jiang, Wei Fan and Xuechun Li

Photonics 2021, 8(4), 97; https://doi.org/10.3390/photonics8040097 - 30 Mar 2021

Cited by 9 | Viewed by 2587

Abstract

In this paper, a model to predict the thermal effects in a flashlamp-pumped direct-liquid-cooled split-disk Nd:LuAG ceramic laser amplifier has been presented. In addition to pumping distribution, the model calculates thermal-induced wavefront aberration as a function of temperature, thermal stress and thermal deformation [...] Read more.

In this paper, a model to predict the thermal effects in a flashlamp-pumped direct-liquid-cooled split-disk Nd:LuAG ceramic laser amplifier has been presented. In addition to pumping distribution, the model calculates thermal-induced wavefront aberration as a function of temperature, thermal stress and thermal deformation in the gain medium. Experimental measurements are carried out to assess the accuracy of the model. We expect that this study will assist in the design and optimization of high-energy lasers operated at repetition rate. Full article

(This article belongs to the Special Issue Laser Amplifiers)

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10 pages, 6981 KiB

Open AccessEditor’s ChoiceArticle

Joule-Level Twelve-Pass LD End-Pumped Bonded Neodymium Glass Laser Amplifier

by Long Pan, Shengzhe Ji, Wenfa Huang, Jiangtao Guo, Xinghua Lu, Jiangfeng Wang, Wei Fan, Xuechun Li and Jianqiang Zhu

Photonics 2021, 8(4), 96; https://doi.org/10.3390/photonics8040096 - 30 Mar 2021

Cited by 2 | Viewed by 3548

Abstract

This paper reports on a Joule-level multi-pass laser amplification device with diode end-pumped square-rod neodymium glass (Nd:glass) bonded to K9 glass. The device generated 1.17 J pulse energy at 1 Hz and 1053 nm. The optical-to-optical efficiency was 13.01%, and the effective energy [...] Read more.

This paper reports on a Joule-level multi-pass laser amplification device with diode end-pumped square-rod neodymium glass (Nd:glass) bonded to K9 glass. The device generated 1.17 J pulse energy at 1 Hz and 1053 nm. The optical-to-optical efficiency was 13.01%, and the effective energy extraction efficiency was 44.23%. Comparing Nd:glass of the same specification without K9 glass under the same conditions, the thermal wave aberration of the former was 85.71% of that of the latter, which is 0.78 um. The near-field modulation degree at the highest energy output was 1.42 within 90% of the spot, and the far-field energy concentration was 81.88% within the 2.5-fold diffraction limit. The Nd:glass bonding method of the square rod is relatively novel in laser amplification systems pumped by the diode end face and can be further studied in future works. Full article

(This article belongs to the Special Issue Laser Amplifiers)

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14 pages, 4296 KiB

Open AccessArticle

Numerical Simulation of Thermo-Optic Effects in an Nd: Glass Slab with Low Thermally Induced Wavefront Distortion

by Xiaoqin Wang, Jiangfeng Wang, Jiangtao Guo, Xinghua Lu, Yamin Wang, Qi Xiao, Wei Fan and Xuechun Li

Photonics 2021, 8(4), 91; https://doi.org/10.3390/photonics8040091 - 26 Mar 2021

Cited by 5 | Viewed by 2935

Abstract

A gain slab configuration with a low thermally induced wavefront distortion, which is based on heating the edge by the cladding layer, is proposed. The gain slab will be applied to a helium-cooled Nd: glass multislab laser amplifier with an output of 100 [...] Read more.

A gain slab configuration with a low thermally induced wavefront distortion, which is based on heating the edge by the cladding layer, is proposed. The gain slab will be applied to a helium-cooled Nd: glass multislab laser amplifier with an output of 100 J at a repetition rate of 10 Hz. Additionally, a 3D numerical simulation model is developed to analyze the thermo-optic effects in the gain slab. Some parameters, including the absorption coefficient (

α

) of the cladding layer, the shape of the pump beam, and the gap between the pump area and absorbing cladding layer, are optimized to eliminate the thermo-optic effects. The results indicate that the peak-to-valley (P-V) of the thermally induced wavefront distortion of the specific gain slab can be reduced by 61% if other parameters remain constant. Full article

(This article belongs to the Special Issue Laser Amplifiers)

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7 pages, 1441 KiB

Open AccessArticle

An Eye-Safe, SBS-Free Coherent Fiber Laser LIDAR Transmitter with Millijoule Energy and High Average Power

by Mehmetcan Akbulut, Leonid Kotov, Kort Wiersma, Jie Zong, Maohe Li, Andy Miller, Arturo Chavez-Pirson and Nasser Peyghambarian

Photonics 2021, 8(1), 15; https://doi.org/10.3390/photonics8010015 - 12 Jan 2021

Cited by 25 | Viewed by 3412

Abstract

We report on an eye-safe, transform-limited, millijoule energy, and high average power fiber laser. The high gain and short length of the NP phosphate-glass fibers enable the SBS-free operation with kW level peak power. The output energy is up to 1.3 mJ, and [...] Read more.

We report on an eye-safe, transform-limited, millijoule energy, and high average power fiber laser. The high gain and short length of the NP phosphate-glass fibers enable the SBS-free operation with kW level peak power. The output energy is up to 1.3 mJ, and the average power is up to 23 W at an 18 kHz repetition rate with 600 ns pulses (peak power > 2.1 kW). The PER is ≈16 dB and the M² of the beam is 1.33 × 1.18. The coherent LIDAR Figure Of Merit (FOM) is 174 mJ*sqrt(Hz), which to our knowledge is the highest reported for a fiber laser. We also report 0.75 mJ energy and >3.7 kW peak power with down to 200 ns pulses and up to 1.21 mJ energy with a 3–5 kHz repetition rate operation of the current system. Full article

(This article belongs to the Special Issue Laser Amplifiers)

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Review

Jump to: Research

24 pages, 12649 KiB

Open AccessReview

Mid-Infrared Few-Cycle Pulse Generation and Amplification

by Kan Tian, Linzhen He, Xuemei Yang and Houkun Liang

Photonics 2021, 8(8), 290; https://doi.org/10.3390/photonics8080290 - 21 Jul 2021

Cited by 25 | Viewed by 7250

Abstract

In the past decade, mid-infrared (MIR) few-cycle lasers have attracted remarkable research efforts for their applications in strong-field physics, MIR spectroscopy, and bio-medical research. Here we present a review of MIR few-cycle pulse generation and amplification in the wavelength range spanning from 2 [...] Read more.

In the past decade, mid-infrared (MIR) few-cycle lasers have attracted remarkable research efforts for their applications in strong-field physics, MIR spectroscopy, and bio-medical research. Here we present a review of MIR few-cycle pulse generation and amplification in the wavelength range spanning from 2 to ~20 μm. In the first section, a brief introduction on the importance of MIR ultrafast lasers and the corresponding methods of MIR few-cycle pulse generation is provided. In the second section, different nonlinear crystals including emerging non-oxide crystals, such as CdSiP₂, ZnGeP₂, GaSe, LiGaS₂, and BaGa₄Se₇, as well as new periodically poled crystals such as OP-GaAs and OP-GaP are reviewed. Subsequently, in the third section, the various techniques for MIR few-cycle pulse generation and amplification including optical parametric amplification, optical parametric chirped-pulse amplification, and intra-pulse difference-frequency generation with all sorts of designs, pumped by miscellaneous lasers, and with various MIR output specifications in terms of pulse energy, average power, and pulse width are reviewed. In addition, high-energy MIR single-cycle pulses are ideal tools for isolated attosecond pulse generation, electron dynamic investigation, and tunneling ionization harness. Thus, in the fourth section, examples of state-of-the-art work in the field of MIR single-cycle pulse generation are reviewed and discussed. In the last section, prospects for MIR few-cycle lasers in strong-field physics, high-fidelity molecule detection, and cold tissue ablation applications are provided. Full article

(This article belongs to the Special Issue Laser Amplifiers)

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