Evaluation of a Novel Ablative 1940 nm Pulsed Laser for Skin Rejuvenation.

Background: Skin rejuvenation is a widely sought-after goal, prompting advancements in laser technology for noninvasive and effective treatments. Ablative lasers, in particular, have evolved to address diverse skin concerns, with fractional ablative lasers offering better-tolerated outcomes. The introduction of a novel ablative Thulium pulsed laser, based on Thulium-doped Yttrium aluminum Perovskite (Tm:YAP) crystal, delivers precise and controlled skin rejuvenation by allowing customization of ablative microcolumns.

Two-mJ level, high-energy all-passive KGW/Tm:YLF Raman laser.

This paper presents an all-passive external cavity KGW Raman laser in the 2-m spectral range, pumped by a Tm:YLF laser at 1879.5 nm. The Raman laser emits two lines at 2197 nm and 2263 nm achieving maximum energy outputs of 1.

Gain-switched Ho:YAG laser with a 3.35-ns pulse duration.

This paper presents a gain-switched Ho:YAG laser at 2090 nm, pumped by a passively Q switched Tm:YLF. A pulse duration of 3.35 ns is achieved with a pulse energy of 0.

Electro-optic active Q-switched Tm:YLF laser based on polarization modulation.

An electro-optic active -switched Tm:YLF laser (1880 nm) employing a novel, to the best of our knowledge, switching scheme is presented. The switching is done by a potassium lithium tantalate niobate (KLTN) crystal operated slightly above the ferroelectric phase transition, cut in a trapezoidal shape for reducing acousto-optic oscillations. The novel switching scheme exploits the emission cross section difference between the and polarizations in the Tm:YLF and overcomes the residual oscillation effects even at high repetition rates.

Efficient all-solid-state passively Q-switched SWIR Tm:YAP/KGW Raman laser.

We present an all-passive efficient KGW Raman laser with an external-cavity configuration in the 2 µm spectral regime. The Raman laser was pumped by a passively -switched Tm:YAP laser emitting at 1935 nm. Due to the bi-axial properties of the KGW crystal, the laser exhibits stimulated Raman emission at two separate spectral lines: 2272 nm and 2343 nm.

Two-wavelength Tm:YLF/KGW external-cavity Raman laser at 2197 nm and 2263 nm.

This paper presents a KGW Raman laser with an external-cavity configuration at the 2 µm region. The Raman laser is pumped by an actively Q-switched Tm:YLF laser, especially designed for this purpose emitting at 1880 nm. Due to the KGW bi-axial properties, the Raman laser is able to lase separately at two different output lines, 2197 nm and 2263 nm.

Carrier-to-envelope phase-stable, mid-infrared, ultrashort pulses from a hybrid parametric generator: Cr:ZnSe laser amplifier system.

Our Cr:ZnSe laser amplifier, seeded by parametric difference mixing, produces 72fs long pulses at the central wavelength of ~2.37µm. The stability of the carrier-to-envelope phase of the amplified seed pulses, attained at the stage of their parametric generation, is preserved through 6 orders of magnitude of laser amplification.

Actively Q-switched tunable narrow bandwidth milli-Joule level Tm:YLF laser.

A pulsed high energy and narrow bandwidth tunable Tm:YLF laser at the milli-Joule level is demonstrated. The spectral bandwidth was narrowed down to 0.15 nm FWHM, while 33 nm of tunability range between 1873 nm and 1906 nm was achieved using a pair of YAG Etalons.

Watt-level tunable narrow bandwidth Tm:YAP laser using a pair of etalons.

We demonstrated in this paper a watt-level tunable, narrow band, end-pumped Tm:YAP laser. Spectral tunability of 35 nm ranging continuously between 1917-1951 nm with a spectral linewidth of 0.15 nm FWHM was achieved.

Diode end-pumped passively Q-switched Tm:YAP laser with 1.85-mJ pulse energy.

Passive Q switching of a Tm:YAP solid-state laser at 1935 nm with Cr:ZnSe and Cr:ZnS polycrystalline saturable absorbers is demonstrated for the first time, to the best of our knowledge. With Cr:ZnS, a maximum pulse energy of 1.85 mJ is obtained for a pulse duration of 35.

Calibration-free pulse oximetry based on two wavelengths in the infrared - a preliminary study.

The assessment of oxygen saturation in arterial blood by pulse oximetry (SpO₂) is based on the different light absorption spectra for oxygenated and deoxygenated hemoglobin and the analysis of photoplethysmographic (PPG) signals acquired at two wavelengths. Commercial pulse oximeters use two wavelengths in the red and infrared regions which have different pathlengths and the relationship between the PPG-derived parameters and oxygen saturation in arterial blood is determined by means of an empirical calibration. This calibration results in an inherent error, and pulse oximetry thus has an error of about 4%, which is too high for some clinical problems.

Respiratory-induced vasoconstriction measured by light transmission and by laser Doppler signal.

Changes in finger tissue blood volume (TBV) measured by light transmission and in laser Doppler flow (LDF) were obtained during long breathing (of 12 s period) and associated with the respiratory phases, inspiration and expiration. For fifteen out of sixteen subjects TBV and LDF started to decrease 0-2 s after the start of expiration and increased during inspiration but the start of increase occurred before the start of inspiration, showing that the respiratory-induced changes in TBV and LDF are mainly associated with the expiration. Decrease of TBV and LDF after expiration was also found during the inspiratory gasps