We report on the first passively mode-locked femtosecond-laser operation of a disordered Yb:Ca3Gd2(BO3)4 crystal using a SEmiconductor Saturable Absorber Mirror (SESAM). Pumping with a ...single-transverse mode fiber-coupled laser diode at 976 nm, nearly Fourier-transform-limited pulses as short as 96 fs are generated at 1045 nm with an average output power of 205 mW and a pulse repetition rate of ~67.3 MHz. In the continuous-wave regime, high slope efficiency up to 59.2% and low laser thresholds down to 25 mW are obtained. Continuous wavelength tuning between 1006–1074 nm (a tuning range of 68 nm) is demonstrated. Yb:Ca3Gd2(BO3)4 crystals are promising for the development of ultrafast lasers at ~1 μm.
•A detailed analysis of different types of photonic sensors such as integrated photonic sensors, optical fiber-based sensors, wearable sensors and metasurface-based sensors is presented.•Insight into ...the latest advancements, emerging challenges, and potential solutions for further developing photonic sensors.
Photonic sensors play a vital role in the modern world, revolutionizing various industries with their efficiency and precision. These sensors utilize light particles (photons) to detect, measure, and analyze different parameters such as light intensity, wavelength, phase, and polarization. One of their key advantages lies in their ability to offer highly sensitive, fast, and accurate measurements across a wide range of applications. In healthcare, they are used in medical imaging technologies like optical coherence tomography for non-invasive diagnostics and imaging of tissues. Additionally, photonic sensors have transformed environmental monitoring, allowing real-time analysis of pollutants, gases, and other substances in air and water. Moreover, their application extends to defence and security, where they are utilized in surveillance, reconnaissance, and laser-based defence systems. In this concise paper, we aim to offer our insights into the latest advancements, emerging challenges, and potential solutions in the ongoing development of photonic sensors.
A comprehensive experimental investigation has been conducted into the high-power continuous-wave (CW) laser performance of isostructural Yb-doped vanadates, including three ordered crystals of ...Yb:YVO 4 , Yb:GdVO 4 , and Yb:LuVO 4 , and two mixed ones with compositional disorder: Yb 0.007 :Y 0.407 Gd 0.586 VO 4 and Yb 0.015 :Lu 0.52 Gd 0.465 VO 4 . The CW laser operation of the different vanadates is compared under nearly identical experimental conditions by using a high-power diode laser as the pump source. In addition to the output characteristics of the individual vanadate lasers, the polarization properties and optical bistability exhibited in the laser oscillation are also discussed. The spectroscopic properties closely related to the laser performance are compared and summarized for these Yb-doped vanadates.
A compact Raman laser gas spectrometer is developed. It comprises a high-power green laser at 532.123 nm as an excitation source and a specially designed gas cell with an internal volume of less than ...0.6 cm3 that can withstand gas pressures up to 100 atm. The resolution of the spectrometer is ~1 cm−1. The Raman spectra of chemically pure isotopically enriched carbon dioxide (12CO2, 13CO2) and methane (12CH4, 13CH4) gases are studied. The expected limit of detection (LOD) is less than 100 ppm for the isotopologues of CO2 and less than 25 ppm for those of CH4 (at a gas pressure of 50 atm.), making the developed spectrometer promising for studying the sources of emissions of greenhouse gases by resolving their isotopologue composition. We also show the suitability of the spectrometer for Raman spectroscopy of human exhalation.
We describe a compact Yb:YAG laser Q-switched by a graphene-based saturable absorber and pumped by a laser diode at 932 or 969 nm. The compact laser generates a maximum average output power value of ...185 mW at 1032 nm with a slope efficiency value of 12%. The shortest duration of the Q-switched pulse achieved is 228 ns at a repetition frequency of 285 kHz. The maximum pulse energy amounts to 0.65 μJ.
We demonstrate continuous wave (CW) room temperature laser operation of the monoclinic Ho(3+)-doped KLu(WO(4))(2) crystal using a diode-pumped Tm(3+):KLu(WO(4))(2) laser for in-band pumping. The ...slope efficiency achieved amounts to ~55% with respect to the absorbed power and the maximum output power of 648 mW is generated at 2078 nm.
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