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. METHODS: A pilot in vivo study was conducted on the abdominal skin of a live female pig. Using the Laser Team Medical (LTM) prototype laser, treatments were administered with varying coagulation settings (minimal and maximum) and energies (32, 80, 120, and 160 mJ per microcolumn). Biopsies were harvested, fixed, and stained for subsequent analysis. The penetration depth and width of the microcolumns were evaluated. RESULTS: Low coagulation settings produced ablative microcolumns with thermal affected zones of 160 µm width, while high coagulation settings resulted in wider zones of 400-530 µm. The ablation cavities' width was estimated to be less than 100 µm in both settings. The novel 1940 nm pulsed laser demonstrated superior microcolumn properties, offering potential advantages such as shorter downtime and increased efficacy compared to existing fractional ablative lasers. CONCLUSION: This study presents encouraging preliminary results regarding the efficacy and safety of the first ablative 1940 nm pulsed laser. The results show ablative microcolumns thinner than the counterpart devices, showing the device safety and potential higher efficacy along with short downtime. The LTM novel ablative 1940 nm pulsed laser holds immense potential for enhancing skin rejuvenation treatments due to its superior microcolumns properties. The versatility of this laser can open new treatment procedures and may extend to different areas of dermatology.

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-µm 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 1.86 mJ and 2.08 mJ, and conversion efficiencies of 40% and 45.3%, respectively. To the best of our knowledge, this laser performance is a new record in terms of energy per pulse and conversion efficiency, surpassing the two-mJ level for the first time by stimulated Raman scattering in the 2-µm range in an all-passive configuration.

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 0.7 mJ at 1.3-kHz repetition rate, corresponding to 209-kW peak power. The pump energy is 2.8 mJ, corresponding to 25% conversion efficiency with 37% slope efficiency. This laser performance with its compact design can be implemented in applications that require short pulse durations that have not been addressed to date.

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

An electro-optic active Q-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 π and σ polarizations in the Tm:YLF and overcomes the residual oscillation effects even at high repetition rates. The laser exhibited stable operation yielding pulses of 0.81 mJ and pulse duration of 30 ns at 5 kHz, and pulses of 1.25 mJ and pulse duration of 19 ns at 500 Hz.

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 Q-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. The output energies achieved at these two lines are 340 µJ/pulse and 450 µJ/pulse, accordingly. The seed to Raman laser conversion efficiencies achieved of 19.2% and 23.5%, respectively, are comparable to actively Q-switched laser arrangements. To the best of our knowledge, this is the first time an efficient Raman laser in the 2 µm regime is demonstrated in a completely passive configuration.