Article
Optics
Ajanta Barh, B. Ozgur Alaydin, Jonas Heidrich, Marco Gaulke, Matthias Golling, Christopher R. Phillips, Ursula Keller
Summary: Femtosecond lasers with high repetition rates are attractive for spectroscopic applications. However, current laser sources at long wavelengths face limitations in output power and repetition rates. This study presents a high-power ultrafast laser oscillator operating at multi-GHz repetition rates using a specific laser modelocked with an SESAM. The results open up possibilities for efficient spectroscopy above 2 μm.
Article
Optics
Yuliya Binhammer, Thomas Binhammer, Robin Mevert, Tino Lang, Angelika Ruck, Uwe Morgner
Summary: The report describes a high power, ultra-broadband, quickly tunable non-collinear parametric oscillator capable of delivering femtosecond pulses in two synchronized output beams. The device is ideal for spectroscopy or multi-color imaging applications, and preliminary results on two-color functional microscopy are presented.
Article
Optics
Jingcheng Shang, Chao Mei, Shengzhi Zhao, Yizhou Liu, Kejian Yang, Chun Wang, Tao Li, Tianli Feng
Summary: This article reports on a 2-mu m all-fiber nonlinear pulse compressor based on normal dispersion fiber, which enables watt-level high-power scaling ability and a high pulse compression ratio. Experimental and numerical analysis results show the performance characteristics of the compressor.
HIGH POWER LASER SCIENCE AND ENGINEERING
(2022)
Article
Optics
Sungkwon Shin, Jun-Gyu Hur, Jong Kab Park, Doh-Hoon Kim
Summary: This study investigated the effects of femtosecond laser beam polarization on the efficiency and symmetry of metal sheet processing. It was found that linear polarization resulted in higher ablation efficiency but asymmetric microstructures, while circular polarization led to lower ablation efficiency but symmetric microstructures. Experimental results verified the asymmetric and symmetric microstructure profiles.
Article
Optics
Freysz Valerian, Freysz Eric
Summary: We report on a femtosecond-pulsed optical parametric oscillator (OPO) that is pumped by a large-mode-area, ytterbium-doped, rod-type fiber laser. By adjusting the pulse polarization inside the laser cavity, the OPO can deliver tunable femtosecond signal pulses at different repetition rates.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Optics
Tadas Bartulevicius, Mykolas Lipnickas, Virginija Petrauskiene, Karolis Madeikis, Andrejus Michailovas
Summary: This study demonstrates a versatile method for burst formation using the active fiber loop (AFL) and showcases the operation of an industrial-grade ultrafast laser system in both single-pulse and GHz-burst regimes, with varying pulse energies and durations.
Review
Optics
Ying-Ying Li, Bo Gao, Chun-Yang Ma, Ge Wu, Jia-Yu Huo, Ying Han, S. Wageh, Omar A. Al-Hartomy, Abdullah G. Al-Sehemi, Lie Liu, Han Zhang
Summary: Mamyshev oscillators (MOs) have shown great potential in producing ultrafast lasers with high peak power. MO technology, based on step-like saturable absorbers and self-similar evolution in the gain fiber, can generate ultrastable femtosecond pulses with high peak power. This review presents the principle of MO, discusses recent progress in advanced output performance, examines different operation wavelengths, and explores potential applications in various fields. The challenges and future directions of MO are also discussed.
LASER & PHOTONICS REVIEWS
(2023)
Article
Multidisciplinary Sciences
Manuel Macias-Montero, Francisco Munoz, Belen Sotillo, Jesus del Hoyo, Rocio Ariza, Paloma Fernandez, Jan Siegel, Javier Solis
Summary: The study reports the fs-laser induced thermophoretic writing of microstructures in compositionally designed silicate glasses, which can be used as infrared optical waveguides. The addition of specific elements to the silicate glass enables the creation of high refractive index contrast, optimizing the functionality of the microstructures.
SCIENTIFIC REPORTS
(2021)
Article
Engineering, Electrical & Electronic
Geyang Wang, Chuan Bai, Li Zheng, Xuan Tian, Haijing Mai, Yang Yu, Wenlong Tian, Zhiyi Wei, Jiangfeng Zhu
Summary: In this letter, a Yb:CaGdAlO4 crystal-based femtosecond regenerative amplifier with a repetition rate of 1 MHz is demonstrated. The amplifier delivers an average output power of 21.8 W with an absorbed pump power of 47.8 W before compression. The slope efficiency and the optical-to-optical efficiency, measured with respect to the absorbed pump power, are 54.9% and 45.6%, respectively. Upon using a grating-pair for compression, 168-fs pulses with pulse energy of 20 mu J and peak power of 105 MW are obtained. Benefiting from the good thermal management and the great optical-optical efficiency, the beam quality (M-2) on both axes is less than 1.2.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2023)
Article
Engineering, Electrical & Electronic
David Benedicto, Antonio Dias, Juan Carlos Martin, Juan-Antonio Valles, Javier Solis
Summary: A new methodology for characterizing active multicore waveguides is proposed, suitable for various types of structures. Characterization of two-core and single-core waveguides allows for determination of material properties and refractive index variations. The validity of the characterization method is supported by experimental and simulation results.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Editorial Material
Engineering, Manufacturing
Koji Sugioka
Summary: The GHz burst mode of femtosecond laser pulses can improve ablation efficiency without deteriorating ablation quality. However, optimizing the parameters involved in GHz burst mode poses challenges for practical implementation. The author’s perspective article examines the history, current status, and future challenges and prospects of this new strategy in femtosecond laser processing.
INTERNATIONAL JOURNAL OF EXTREME MANUFACTURING
(2021)
Article
Optics
Blake S. Dastrup, Eric R. Sung, Frank Wulf, Clara Saraceno, Keith A. Nelson
Summary: Utilizing total internal reflection to increase the distance of optical rectification and achieving velocity matching through angle tuning can significantly enhance terahertz spectral amplitude. However, further enhancement is limited by 3-photon absorption and divergence of the pump beam.
LIGHT-SCIENCE & APPLICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Wen-Chi Wang, Shun-Fa Wang, Teruki Sugiyama
Summary: This study demonstrates polymorph control of amino acids using high-repetition-rate femtosecond laser pulses, showing that two types of L-serine polymorphs can be produced by irradiating a saturated aqueous solution of L-serine. Different polarization of the laser leads to the formation of different polymorphs, with left-circular polarization producing Form 1 and all other polarizations producing Form 2.
JOURNAL OF THE CHINESE CHEMICAL SOCIETY
(2022)
Article
Optics
Hongling Chen, Peixiong Zhang, Jiawan Song, Hao Yin, Yin Hang, Qiguo Yang, Zhen Li, Zhenqiang Chen
Summary: The introduction of Gd3+ ions in the novel Nd:CaY0.9Gd0.1AlO4 mixed crystal broadened its emission band and enabled successful diode-pump tunable laser operation. This development is significant for the further advancement of near-infrared tunable lasers.
Article
Optics
Gian-Luca Roth, Stefan Kefer, Steffen Hessler, Cemal Esen, Ralf Hellmann
Summary: The study presents the fabrication of integrated photonic crystal waveguides inside transparent polymers using femtosecond lasers. By generating hexagonal photonic lattice-like waveguides, the limitations caused by minor refractive index changes are overcome, allowing for light confinement and transmission.
LASER & PHOTONICS REVIEWS
(2021)
Editorial Material
Optics
Jacob I. Mackenzie
APPLIED PHYSICS B-LASERS AND OPTICS
(2022)
Review
Optics
Marek Stehlik, Goby Govindassamy, Janis Zideluns, Fabien Lemarchand, Frank Wagner, Julien Lumeau, Jacob Mackenzie, Laurent Gallais
Summary: The laser damage properties of dielectric sesquioxide films fabricated by pulsed-laser deposition were compared with established optical-coating materials. Results showed that the sesquioxides exhibited high laser damage thresholds, making them suitable for high-power resistant optical components for ultrashort-pulse lasers.
OPTICAL ENGINEERING
(2022)
Article
Optics
Piyush Raj, Reena Parihar, Rajveer Dhawan, Amol Choudhary
Summary: We propose a novel approach to realize wideband reconfigurable, Brillouin-based microwave photonic bandpass filters employing RF interferometry and advanced phase engineering. The filters exhibit high selectivity, wide bandwidth, and low power requirements. The filters also have a flat phase response, zero group delay, and are not affected by Brillouin noise in the passband.
Article
Optics
Naveenta Gautam, Vinay Kaushik, Amol Choudhary, Brejesh Lall
Summary: This paper presents a unique approach using a deep convolutional neural network to solve the nonlinear Schrodinger equation for learning the pulse evolution. A knowledge distillation-based technique is applied to compress the model. The results show that even with a reduction of up to 91.2% in model size, the achieved mean square error is very close to that of the teacher model.
Article
Engineering, Electrical & Electronic
Mukund Jha, Rajveer Dhawan, Reena Parihar, Amol Choudhary
Summary: This study proposes a method to compensate for transmission nulls in phase-modulated analog photonic links by superimposing a stimulated Brillouin scattering gain response. The operating bandwidth of the link is increased and multiple null compensation is demonstrated. The method is also shown to have tunability across different bands and link gain improvement is achieved through balanced detection.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2022)
Article
Physics, Condensed Matter
Lazar K. Anlin, K. V. Vijoy, K. Pradeesh, Shibi Thomas, Honey John, K. J. Saji
Summary: This study involves modifying the properties of poly dimethyl siloxane (PDMS) by embedding it with metal nanoparticles and fabricating TENGs based on metal nanoparticle/PDMS composites. The electrical characteristics of these composites are examined, revealing that the filler with the best conductivity exhibits excellent properties.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Engineering, Electrical & Electronic
K. Girish, Reena Parihar, Piyush Raj, Amol Choudhary
Summary: In this letter, a novel approach to realize a wideband, reconfigurable, and tunable Brillouin-based microwave photonic bandstop filter using RF phase engineering is proposed and experimentally demonstrated. The filter achieves suppression of > 15 dB for moderate bandwidths and maximum bandwidth reconfigurability up to 1 GHz by utilizing two pumps with specific powers. Moreover, switching from a bandpass to a bandstop filter is achieved through simple phase manipulations. The proposed filter is highly power-efficient compared to conventional Brillouin systems.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Rajveer Dhawan, Kartik Moyal, Amol Choudhary
Summary: Frequency modulated continuous wave (FMCW) radar uses photonics-based de-chirp processing to determine the range by monitoring the frequency difference between transmitted and received signals. This approach overcomes the limitations of traditional optical filters and allows for operation in different frequency bands. The proposed model is validated through theoretical analysis, simulation, and experimental testing, demonstrating its ability to detect multiple targets with high resolution and accurately estimate target widths.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2023)
Article
Optics
Georgia Mourkioti, Danish Bashir, Goby A. Govindassamy, Fangfang Li, Robert W. Eason, Thomas Graf, Marwan Abdou Ahmed, Jacob I. Mackenzie
Summary: This paper presents the fabrication and first demonstration of all-dielectric crystalline grating-waveguide reflectors consisting of a Sc2O3 waveguide grown on a sub-wavelength-patterned sapphire substrate. Rigorous coupled-wave analysis is used to simulate the structure, showing a theoretically 100% resonance reflectivity. The sapphire substrate is patterned using inductively coupled plasma etching, while the Sc2O3 crystalline waveguide is grown through pulsed laser deposition. Devices with distinct TE- and TM-polarisation resonances are demonstrated, with reflectance close to 90% at an angle of incidence near 10 degrees. Refining the fabrication processes and tolerances should improve the surface quality and achieve resonance reflectivity closer to the ideal state.
APPLIED PHYSICS B-LASERS AND OPTICS
(2023)
Article
Optics
Rajveer Dhawan, Debashis Parida, Reena Parihar, Mukund Jha, Amol Choudhary
Summary: This paper proposes and experimentally demonstrates a photonic-based generation scheme for carrier frequency multiplication of LFM waveforms. The scheme utilizes a single dual-drive Mach-Zehnder modulator to generate multi-band LFM signals, with frequency band selection through a Brillouin RF filter. The experimental results verify the flexibility and versatility of the system.
Article
Engineering, Electrical & Electronic
Reena Parihar, Rajveer Dhawan, Amol Choudhary
Summary: In this paper, a microwave photonic phase shifter using stimulated Brillouin scattering is proposed to improve the dynamic range and noise performance by low-biasing the carrier. Mathematical expressions for the performance metrics of the analog photonic link are derived and experimentally optimized for the first time. The carrier is subjected to gain and loss responses, and low-biasing is achieved using unbalanced loss and gain pumps, resulting in improved performance. Real-life applications and potential uses of the Brillouin RF phase shifter are also demonstrated.
IEEE JOURNAL OF QUANTUM ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Mukund Jha, Rajveer Dhawan, Reena Parihar, Amol Choudhary
Summary: In this article, a novel approach to realize a switchable RF filter with analogous EIA, EIT, and spectral hole burning responses is proposed. The filters demonstrate high absorption depth and bandwidth tunability, as well as high transmission depth and spectral hole burning depths. The proposed method is highly power-efficient.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Proceedings Paper
Optics
Marek Stehlik, Goby Govindassamy, Janis Zideluns, Fabien Lemarchand, Frank Wagner, Julien Lumeau, Jacob Mackenzie, Laurent Gallais
Summary: Crystalline sesquioxide films produced by pulsed-laser deposition showed similar laser damage resistance to amorphous magnetron-sputtered thin films. This finding is crucial for the design of damage resistant reflective components used in ultrashort-pulse lasers.
SPIE LASER DAMAGE: LASER-INDUCED DAMAGE IN OPTICAL MATERIALS 2022
(2022)
Proceedings Paper
Materials Science, Multidisciplinary
Kondankunnath Rejith Resmi, Pradeesh Kannan
Summary: In this study, surface plasmon coupled emission (SPCE) was demonstrated by coupling a Metal-Dielectric-Metal Planar (MDMP) structure to a hemicylindrical prism using the Reverse Kretchmann configuration. The results showed that higher dielectric thickness enhanced the emission efficiency.
MATERIALS TODAY-PROCEEDINGS
(2022)
Proceedings Paper
Materials Science, Multidisciplinary
Lisha C. Lohithakshan, Pradeesh Kannan
Summary: Anti-reflection (AR) coatings, distributed Bragg reflectors (DBRs), Comb filters, and dichroic mirrors were designed using multi-layered thin films and simulated using transfer matrix model (TMM). The designs include a tri-layered AR coating to increase zero-reflectance window, multi-layered DBRs and dichroic filters using alternating high and low refractive index materials, and comb filters sandwiched between two DBRs.
MATERIALS TODAY-PROCEEDINGS
(2022)
