Dual-wavelength Laser Research Articles

Orthogonally polarized dual-wavelength Nd:LiYF4 laser at 1777 and 1789 nm with 1:1 output power ratio

Abstract A diode-pumped continuous-wave orthogonally polarized dual-wavelength Nd:LiYF4 (Nd:YLF) laser on 4F3/2 → 4I15/2 transition is studied. The output power ratio can be adjusted using two intracavity uncoated glass plates. At an incident pump power of 20 W, a dual-wavelength laser operating at 1777 nm in π-polarization and 1789 nm in σ-polarization was realized. The total output power of the dual-wavelength laser was more than 1.16 W with a 1:1 output power ratio. The total slope efficiency and total optical conversion efficiency with respect to the incident pump power were 4.6% and 2.9%, respectively. To the best of our knowledge, this is the first work realizing mid-infrared wavelength operation in Nd:YLF lasers on 4F3/2 → 4I15/2 transition.

Generation of stable dual-wavelength mode-locked pulses using boron nitride saturable absorber in all-polarization-maintaining Er-doped fiber laser

This work demonstrates the generation of stable dual-wavelength mode-locked pulses using boron nitride (BN) as a novel saturable absorber within a polarization-maintaining (PM) Er-doped fiber laser cavity. BN was chosen due to its exceptional properties, including high thermal stability, wide bandgap, and excellent mechanical strength. A drop-casting technique was employed to fabricate the BN-based saturable absorber. The laser generated high-quality dual-wavelength pulses centered at 1566.3 nm and 1575.6 nm with a repetition frequency of 25.3 MHz and a pulse width of 900 ps. The generated laser exhibited excellent stability and a high degree of polarization (DOP) of 99.8 %. These findings contribute to the advancement of dual-wavelength mode-locked fiber laser technology and open new avenues for applications such as dual-frequency comb spectroscopy.

Efficacy and Safety of Non-Ablative Dual Wavelength Diode Laser Therapy for Genitourinary Syndrome of Menopause: A Single-Center Prospective Study.

This study evaluates the efficacy and safety of non-ablative diode laser therapy for genitourinary syndrome of menopause (GSM) in post-menopausal women unable to use hormonal therapies. A pilot prospective study was conducted from September 2023 to April 2024, involving 22 post-menopausal women aged 45-73years. Participants underwent three sessions of diode laser treatment with the Leonardo® dual-wavelength Diode laser. Assessments were made at baseline, 3months, and 6months post-treatment. Main outcome measures included Visual Analog Scale (VAS) scores for GSM symptoms, Vaginal Health Index Score (VHIS), and sexual function evaluated using the Female Sexual Function Index (FSFI-6), Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12), and Sexual Quality of Life-Female (SQOL-F) questionnaire. Significant improvements were observed in VHIS, increasing from 12 to 19.27 at 6months (p<0.001). GSM symptoms improved significantly: vaginal dryness scores decreased from 7.72±2.37 to 3.72±2.53, burning sensation scores dropped from 6.00±3.22 to 1.90±1.81, and dyspareunia scores reduced from 8.09±2.11 to 3.90±2.58 (all p<0.016). Sexual function improved, indicated by FSFI-6 scores increasing from 12.27±7.29 to 19.30±6.24 (p<0.016) and SQOL-F scores rising from 63.18±22.93 to 71.45±23.31. No adverse events were reported. Non-ablative diode laser therapy is effective and safe for managing GSM symptoms in post-menopausal women, offering significant symptom relief and enhancing sexual health without serious side effects. Further research with a larger cohort and extended follow-up is needed to confirm these findings. Clinical Trials ID NCT06503003.

Mechanism analysis of dual wavelength laser welding AlN-PC joint based on microtexture treatment

High-strength interfacial bonding between ceramics and transparent polymers is hardly to be achieved, especially in the field of optical packaging of biochips. This paper proposes a novel laser welding method that enhances the joint strength between aluminum nitride (AlN) ceramic and polycarbonate (PC) by laser surface microtexturing. The study investigates the influence of welding methods and microtextures on welding effectiveness, elucidating the bonding mechanisms of the joints. The obtained results showed that dual wavelength laser welding effectively achieves the connection between AlN ceramic and PC. Laser microtexturing increases surface roughness and contact area, leading to stronger mechanical interlocking and overall joint strength. The highest shear strength reached up to 14.66 MPa with longitudinal grooves microtexture. The laser microtexturing improves the hydrophilicity of the AlN surface, facilitating more effective bonding between the materials. The bonding mechanisms at the joint interface include both mechanical interlocking and chemical bonding. Microtexturing improves the stress distribution at the joint interface. The formation of C-O-Al chemical bonds at the interface effectively enhances the joint strength. Longitudinal grooves microtexture exhibit a higher substrate fracture rate due to stress concentration and capillary pores. In contrast, staggered square holes microtexture provide superior mechanical performance through uniform stress distribution and robust mechanical interlocking.

Dual-wavelength lasing in an erbium-doped fiber cavity with a nested magnesium fluoride microcavity

Dual-wavelength lasing in an erbium-doped fiber cavity with a nested magnesium fluoride microcavity

Switchable Dual-Wavelength Fiber Laser with Narrow-Linewidth Output Based on Parity-Time Symmetry System and the Cascaded FBG

In this paper, a dual-wavelength narrow-linewidth fiber laser based on parity-time (PT) symmetry theory is proposed and experimentally demonstrated. The PT-symmetric filter system consists of two optical couplers (OCs), four polarization controllers (PCs), a polarization beam splitter (PBS), and cascaded fiber Bragg gratings (FBGs), enabling stable switchable dual-wavelength output and single longitudinal-mode (SLM) operation. The realization of single-frequency oscillation requires precise tuning of the PCs to match gain, loss, and coupling coefficients to ensure that the PT-broken phase occurs. During single-wavelength operation at 1548.71 nm (λ1) over a 60-min period, power and wavelength fluctuations were observed to be 0.94 dB and 0.01 nm, respectively, while for the other wavelength at 1550.91 nm (λ2), fluctuations were measured at 0.76 dB and 0.01 nm. The linewidths of each wavelength were 1.01 kHz and 0.89 kHz, with a relative intensity noise (RIN) lower than −117 dB/Hz. Under dual-wavelength operation, the maximum wavelength fluctuations for λ1 and λ2 were 0.03 nm and 0.01 nm, respectively, with maximum power fluctuations of 3.23 dB and 2.38 dB. The SLM laser source is suitable for applications in long-distance fiber-optic sensing and coherent LiDAR detection.

A decade of mid-infrared, 3.5 µm dual-wavelength pumped fiber lasers, review and perspective

A decade of mid-infrared, 3.5 <i>µ</i>m dual-wavelength pumped fiber lasers, review and perspective

A Single-Center, Open-Label, Prospective Study of a 589/1319 nm Dual Wavelength Laser for the Treatment of Facial Hyperpigmentation.

Facial hyperpigmentation, characterized by the excessive production of melanin in the skin, is a prevalent dermatological concern affecting individuals of various ethnic backgrounds. To evaluate the safety and efficacy of a multi-wavelength 589/1319 nm dual-pulse duration laser device for the treatment of hyperpigmentation Patients/Methods: A total of 17 healthy women (mean [SD] age of 43.4 [11.6] with skin phototype II-IV) were enrolled in this prospective, single-center study. Eligible participants received up to 3 treatments spaced 3 to 5 weeks apart with 2 follow-up visits at 4 and 12 weeks after the final treatment. Assessments included investigator ratings of skin quality, global aesthetic improvement, and hyperpigmentation. Safety and tolerability were monitored throughout the study. Significant improvements in hyperpigmentation and skin quality were observed at the 2 follow-up visits from baseline in most patients per investigator assessments. Patient satisfaction was high, and treatments were safe with transient self-resolving side effects such as erythema. Laser treatments using a dual-wavelength 589/1319nm device significantly improve facial hyperpigmentation in patients of various skin types. J Drugs Dermatol. 2024;23(11):943-947. doi:10.36849/JDD.8196.

Evaluation of Ovarian Reserve and Recurrence Rate After DWLS Diode Laser Ovarian Endometrioma Vaporization (OMAlaser): A Prospective, Single-Arm, Multicenter, Clinical Trial

Study ObjectiveTo evaluate the effectiveness of the Dual Wavelength Laser System (DWLS) diode laser on the treatment of ovarian endometrioma (OMA), with ablation and vaporization of the cystic capsule without performing the stripping technique, in terms of ovarian reserve and recurrence rate. DesignProspective, single-arm, multicenter, clinical trial. SettingMulticenter University Hospital. PatientsSeventy patients with symptomatic OMA. InterventionsPatients underwent surgery for primary unilateral or bilateral symptomatic OMA treated with DWLS diode laser vaporization. Following surgical intervention, patients were enrolled in a 12 months surveillance protocol featuring regular clinical assessments aimed at detecting ovarian reserve, pregnancy rate and any recurrence of the cyst and/or symptomatic relapse. Measurements and Main ResultsAntimullerian hormone (AMH) levels at the 3-month follow-up exhibited a significant difference from the baseline (p = .034), demonstrating a return to nearly presurgical values in the subsequent months. Antral follicle count (AFC) of the operated ovary showed a significant increase after treatment at the 6-month and 12-month follow-up (p = 0.005 and p = 0.002, respectively). Pregnancies were documented in 48.3% (14/29) of infertile patients who underwent treatment. OMA recurrence was observed in 4 patients (5.7%) at 12 months. No patient exhibited a significant relapse of the analyzed symptoms compared to baseline values. ConclusionThe findings of this study propose that DWLS diode laser presents a good option for treating OMA, demonstrating minimal impact on the surrounding healthy ovarian tissue, favorable pregnancy rate, coupled with low recurrence rates.

Arrayed waveguide gratings (AWGs) in ZBLAN fibers for switchable dual-wavelength fiber lasers in the O- and S-band regions

Arrayed waveguide gratings (AWGs) in ZBLAN fibers for switchable dual-wavelength fiber lasers in the O- and S-band regions

Design and wavelength selection of compact dual-wavelength Yb:YAG lasers with a Z-shaped cavity

The compact dual-wavelength Yb:YAG lasers were designed and developed by employing a Z-shaped cavity. The overall cavity length is about 32 cm, which can be packaged in a device size of 15 × 10 cm2. The oscillating beam radius in the laser crystal varied by the cavity length, and stable dual wavelength laser was achieved. The 1050 nm output of 1.44W was obtained at the highest pump power is 10 W when the oscillating beam radius was 125 μm. The balance dual-wavelength output of 0.93W was achieved with the optical to optical conversion efficiency of 9.3%. The output wavelengths of the Yb:YAG laser depended on the oscillating beam radius, which was consistent with the experimental results. Our findings indicated that while stringent mode matching was ideal, there was a degree of flexibility that can be tolerated without significantly compromising the laser's performance, which can be beneficial for the dual-wavelength oscillation in applications.

Impact of dual wavelength laser therapies in the treatment of hypertrophic scars and keloids: a systematic review

Impact of dual wavelength laser therapies in the treatment of hypertrophic scars and keloids: a systematic review

Orthogonally polarized dual-wavelength Pr:LiYF4 lasers in 1.3 μm region

We report a continuous-wave (CW) orthogonally polarized dual-wavelength Pr:LiYF4 laser in 1.3 μm region pumped by a Yb-doped fiber laser. The gain and loss of the wavelengths in the orthogonally polarized directions were balanced by an inclined etalon inserted into the cavity. At an absorbed pump power of 9.2 W, a dual-wavelength laser operating at 1310 nm in π-polarization and 1326 nm in σ-polarization with 2.26 W of total output power was achieved. Moreover, by continuing to adjust the tilt angle of the etalon, the three other pairs of dual-wavelengths (1289 and 1306 nm, 1289 and 1306 nm, and 1306 and 1310 nm) were also obtained. The output power ratio of each pair of dual wavelengths was nearly 1:1. To the best of our knowledge, this is the first work realizing the Pr:LiYF4 laser operating in 1.3 μm region.

Diode-pumped dual-wavelength Nd:YVO4/Nd:CTGAS laser

LD pumped dual-wavelength lasers have great application potential in scientific and technical scopes. In this paper, we reported a novel dual-wavelength laser by combining Nd:YVO4 and Nd:CTGAS crystals. For 1064 nm and 1068 nm dual-wavelength laser operation, the maximum continuous-wave output power was 929 mW, corresponding to an optical conversion efficiency of 38.7 %. With a Cr:YAG crystal as the saturable absorber, the maximum passively Q-switched output power was 239 mW, giving a shortest pulse width of 20.8 ns and an optical conversion efficiency of 17.1 %.

Diode-pumped continuous-wave single- and dual-wavelength Yb:GMBO lasers

The diode-pumped continuous-wave (CW) single- and dual-wavelength Yb:GdMgB5O10 (Yb:GMBO) lasers were demonstrated. The thermal lens focal lengths of the Yb:GMBO crystal in the directions of the Y and Z axes was calculated and measured, and the sizes of the wavelengths in the Yb:GMBO crystal was calculated for optimal mode matching between laser and pump beams. A birefringent filter (BF) was placed in the linear cavity for wavelength tuning at 1011, 1035, and 1059 nm, respectively. Among these wavelengths, 1011 and 1035 nm were realized for the first time. Additionally, by rotating the BF and changing the transmittance of the output coupler, the gain and loss of the emission lines were balanced, and simultaneous dual-wavelength laser operating at 1035 and 1059 nm, 1011 and 1035 nm, 1011 and 1059 nm was obtained, respectively.

Dual-wavelength solid-state Raman laser at 555 and 579.5 nm for spectrophotometric determination of carboxyhemoglobin

For accurate measurement of carboxyhemoglobin level in the blood, a compact dual-wavelength laser at 555 and 579.5 nm with conversion efficiency up to 27.5% is originally developed by using Nd:YVO4/KGW/LBO laser with intracavity stimulated Raman scattering (SRS), second harmonic generation (SHG), and sum frequency generation (SFG). The SRS material is an Np-cut KGW crystal to produce the Stokes wave at 1159 nm from the fundamental wave at 1064 nm. The SHG of the Stokes wave and the SFG of the Stokes and fundamental waves are efficiently achieved by employing two LBO crystals. The temperature of the first LBO crystal is steadily fixed at the optimal phase-matching for generating the output power at 579.5 nm, whereas the temperature of the second one is varied to manipulate the power ratio between the yellow and green emissions. At the balanced temperature of the second LBO crystal, the output powers of the yellow and green emissions can simultaneously reach 5.5 W at a pump power of 40 W.

Singlet fission photovoltaic cells as dual-wavelength laser power converters compatible with highly efficient solar cells

I applied photovoltaic cells equipped with singlet fission (SF) of molecular systems to dual-wavelength laser power converters (DW-LPCs) that efficiently convert two laser lights of different wavelengths to electricity. When the SF-DW-LPC is illuminated by eye-safe laser light of 1470 nm wavelength emitted from a laser diode, a single photon is converted to a single carrier. On the other hand, a single high-energy photon emitted from a high-power and low-cost laser diode of 808 nm is converted to two carriers by SF owing to its endothermic feature, even though the photon energy is slightly lower than twice the fundamental energy gap. Furthermore, the SF-DW-LPC operates as a highly efficient solar cell. These functions are required for optical wireless power transmission to moving objects including electric vehicles and flying drones. I modeled the photovoltaic process with SF and evaluated the limiting conversion efficiencies by detailed-balance calculations. Conversion efficiencies of the SF-DW-LPC for these two laser lights are competitive with those of the conventional single-junction LPCs dedicated to these wavelengths, respectively. The efficiency under solar light is close to that of the optimally designed SF solar cell. Furthermore, the SF-DW-LPC outperforms other types of DW-LPCs designed on the basis of intermediate band, triplet–triplet annihilation, and multiple exciton generation solar cells. Endothermic SF and carrier/energy extraction into the neighboring acceptors have already been demonstrated. However, molecular systems that apply to 1470 nm have not yet been realized, which is the top-priority issue to be solved to realize highly efficient SF-DW-LPCs.

High-power single-frequency continuous-wave 355 nm UV laser via a frequency-correlated dual-wavelength laser.

An all-solid-state single-frequency continuous-wave (CW) 355 nm ultraviolet (UV) laser based on a dispersion-compensated doubly resonant resonator is presented in this Letter that is achieved by employing homemade high-stability all-solid-state frequency-correlated dual-wavelength lasers at 1064 and 532 nm and a temperature-controlled type-I critical-phase-matching LiB3O5 (LBO) to act as the fundamental laser source and the nonlinear medium, respectively. The frequency-correlated dual-wavelength single-frequency CW laser supplies the fundamental frequency 1064 and 532 nm lasers with good frequency synchronization. And the temperature-controlled LBO acts as the dispersion-compensation element to realize double resonance of the 1064 and 532 nm laser. Finally, a 4.2 W high-stability 355 nm UV laser is experimentally obtained, and the corresponding total conversion efficiency is up to 20.5%. To the best of our knowledge, this is the highest power reported about single-frequency CW 355 nm UV laser. The presented method can pave a way to develop a compact single-frequency 355 nm UV laser with high output power.

Impact of Photobiomodulation on IL1β and TGFβ-1 concentrations in patients with aphthous stomatitis.

Laser therapy has shown effectiveness in promoting wound healing by influencing various physiological factors such as blood flow, cytokines, histamine, nerve signals, lymphocyte function, tissue oxygenation, and cell growth. This study aims to evaluate the therapeutic efficacy of Photobiomodulation (PBM) treatment, by using diode laser, in modifying the levels of interleukin-1 beta (IL1β) and transforming growth factor beta-1 (TGFβ-1) in patients diagnosed with aphthous stomatitis. A before-after interventional design was conducted over 10 months with 20 subjects. Data on demographic details and serum concentrations of IL1β and TGFβ-1 were collected pre-treatment and on Days 3 and 7 post-treatments. The intervention involved a single session of four 30-second applications of a QuickLase dual-wavelength laser operating at 980nm. Results show significant reductions in IL1β and TGFβ-1 levels after 7 days of treatment, indicating a time-dependent effect of PBM therapy on these inflammatory markers. The findings suggest that PBM therapy holds promise as an intervention for reducing inflammation associated with aphthous stomatitis.

Unveiling the photoluminescence mechanisms of carbon dots through tunable near-infrared dual-wavelength lasing

Unveiling the photoluminescence mechanisms of carbon dots through tunable near-infrared dual-wavelength lasing