Alexandrite

IMPORTANCE: Hirsutism represents a significant concern for women with polycystic ovary syndrome (PCOS), with deleterious psychological effects warranting acknowledgment and a clear imperative to provide effective management. To our knowledge, this is the first review to exclusively examine the effectiveness of laser and light-based therapies in addressing hirsutism in women with PCOS. OBJECTIVE: To synthesize the existing literature regarding the effectiveness of laser and light hair reduction therapies, either as stand-alone treatments or in combination with systemic agents, in treating hirsutism for women with PCOS...

Understanding of pump-induced lensing in laser amplifiers is essential for the optimized design of high-power lasers with high spatial quality, but there is usually incomplete knowledge of the interplay between thermal and population induced lensing mechanisms, lensing under lasing and non-lasing conditions, and transient lensing effects under pulsed operation. This paper provides quantitative insight of pump-induced lensing effects by using experimental transient pump-probe measurements in an alexandrite laser amplifier end-pumped by a short pulse pump beam with Gaussian spatial intensity distribution...

BACKGROUND: Fordyce angiokeratoma, a benign tiny lesion usually on the scrotum, increases with age and may cause symptoms like itching and bleeding in nearly half of the cases. Although treatment is not always necessary, it is primarily considered for cosmetic reasons in the case of larger or atypical lesions. CASE REPORT: We present the case of a healthy adult male with multiple large red-blue hyperkeratotic nodules and papules on his scrotal skin, causing bleeding upon minor trauma and personal embarrassment...

We report on laser cooling of a large fraction of positronium (Ps) in free flight by strongly saturating the 1^{3}S-2^{3}P transition with a broadband, long-pulsed 243 nm alexandrite laser. The ground state Ps cloud is produced in a magnetic and electric field-free environment. We observe two different laser-induced effects. The first effect is an increase in the number of atoms in the ground state after the time Ps has spent in the long-lived 2^{3}P states. The second effect is one-dimensional Doppler cooling of Ps, reducing the cloud's temperature from 380(20) to 170(20) K...

We present an intra-cavity frequency doubled Q-switched diode-pumped alexandrite ring-laser directly emitting in the UV at 386 nm. Using LBO as nonlinear crystal, the laser yields a pulse energy up to 3 mJ at 500 Hz with an excellent beam quality of M2  = 1.1. The pulse length is about 920 ns, allowing for very narrow bandwidth in single longitudinal mode operation. The optical-to-optical efficiency for the UV laser is > 9% and almost unchanged compared to the fundamental laser...

BACKGROUND: Several different parameters play a role in the transition of hair follicles to the anagen phase, with the role of androgens, progesterone, estrogen hormones, and receptors being significant. OBJECTIVES: The effectiveness of Laser Hair Removal (LHR) and pain tolerance during application were investigated during three different phases of the menstrual cycle. METHODS: 48 axillae were randomly divided into three groups: menstruation, ovulation, and luteal...

BACKGROUND: Laser hair removal (LHR) is one of the most requested cosmetic procedures worldwide. A rare side effect is the appearance of excess hair around previously treated areas, known as paradoxical hypertrichosis. OBJECTIVES: The aim of this study was to retrospectively identify the cause of this side effect. METHODS: This study included all patients who underwent LHR at our center between November 2018 and November 2020. Alexandrite laser (Hair Removal [HR]) or diode laser (Super Hair Removal [SHR]) were used in 70% and 30% of cases, respectively...

OBJECTIVES: Pulsed laser treatment of melasma has shown some promising results. To compare the effectiveness and safety of 755-nm picosecond alexandrite laser (PSAL) fitted with diffractive lens array (DLA) versus 1064-nm Q-switched neodynimum:yttrium aluminum garnet laser (QSNYL) for the treatment of melasma. METHODS: We conducted a randomized, split face controlled, 2-year follow-up study. Each face was divided into two parts, each side receiving three treatments with either PSAL or QSNYL at 1 month intervals...

INTRODUCTION: Pigmentary changes can be bothersome and affect one's well-being. Laser therapy has been shown to effectively treat such skin discolouration. We aimed to assess the utility of a 755 nm alexandrite laser in pigmented lesions removal. MATERIALS AND METHODS: A total of 109 patients aged 44.17 ± 8.2 years were enrolled and underwent laser treatment of facial skin hyperpigmentation. The efficacy was analysed on the basis of photographic diagnosis using the VISIA Complexion Analysis System...

Acanthosis nigricans (AN) is a cutaneous disorder identified by well-defined pigmented plaques mostly detected on skin folds. Timely diagnosis and treatment of AN is essential as it could be an early manifestation of an underlying condition. The treatment of choice for AN has not been determined yet. Our study aimed to compare the efficacy and safety of various lasers with topical medications, including cream and peel. PubMed, Scopus, and Web of Science databases, as well as the Google Scholar search engine, were thoroughly searched until May 1st, 2023...

Laser therapy has shown promising outcomes in treating infantile hemangiomas. However, the molecular mechanisms underlying laser treatment for IH remain incompletely elucidated. This study aimed to unravel the molecular mechanisms of laser therapy in IH treatment. We evaluated the inhibitory effects of laser treatment on the proliferation and promotion of apoptosis in human hemangioma endothelial cells (HemECs) through cell counting kit-8 (CCK-8) assay, Hoechst 33342 staining, and flow cytometric analysis. Transcriptome sequencing analysis of HemECs following laser treatment revealed a significant decrease in the expression level of the GSTM5 gene...

Melasma is a skin dyspigmentation condition that disproportionately affects women, particularly those of Latino, Black, and Asian ethnicities, significantly impacting their quality of life. Efforts to identify effective treatment options have led to the exploration of picosecond laser technology which utilizes brief pulse durations to break down pigment while minimizing thermal damage to surrounding tissue. The 755-nm alexandrite picosecond laser, currently FDA approved for benign pigmented lesion removal, including melasma, is a promising solution...

BACKGROUND: Hidradenitis suppurativa is a chronic inflammatory skin disease characterised by recurrent inflammatory lesions and skin tunnels in flexural sites such as the axilla. Deroofing of skin tunnels and laser treatment are standard hidradenitis suppurativa interventions in some countries but not yet introduced in the United Kingdom. OBJECTIVE: To understand current hidradenitis suppurativa management pathways and what influences treatment choices to inform the design of future randomised controlled trials...

In this work, we investigate the spectroscopic properties of photochromic alexandrite and cordierite by TD-DFT. The objective is to assess the TD-DFT for the simulation of pleochroism (change of color depending on the crystallographic direction of the observation) and the change of color as a function of the light source. For these simulations, we compared an embedding where dangling bonds are saturated by hydrogen atoms and an electrostatic embedding. The electrostatic embedding provided numerically more stable results and allowed a good reproduction of the pleochroism of cordierite, based on a Fe2+ -Fe3+ intervalence charge transfer transition...

We investigate high-energy mJ-class diode-pumped acousto-optic (AO) Q-switched alexandrite lasers with broad tunability at both the fundamental near-IR wavelength range and second harmonic generation (SHG) in the UV wavelength range. An AO Q-switched alexandrite laser with continuous-wave diode-pumping has been operated at up to 10 kHz and producing pulse energy of 700 µJ at repetition rate of 1 kHz. With pulsed double-pass diode-pumping, we demonstrate higher pulse energy of 2.6 mJ. With wavelength tuning, this laser system demonstrated broad fundamental tuning range from 719 to 787 nm with diffraction-limited beam quality (M2  = 1...

BACKGROUND: People with Neurofibromatosis Type 1 (NF1) suffer disfigurement and pain when hundreds to thousands of cutaneous neurofibromas (cNFs) appear and grow throughout life. Surgical removal of cNFs under anesthesia is the only standard therapy, leaving surgical scars. OBJECTIVE: Effective, minimally-invasive, safe, rapid, tolerable treatment(s) of small cNFs that may prevent tumor progression. METHODS: Safety, tolerability, and efficacy of four different treatments were compared in 309, 2-4mm cNFs across 19 adults with Fitzpatrick skin types (FST) I-IV: radiofrequency (RF) needle coagulation, 755nm alexandrite laser with suction, 980nm diode laser, and intratumoral injection of 10mg/mL deoxycholate...

We report a femtosecond Kerr-lens mode-locked (KLM) Alexandrite laser resonantly pumped by a 589 nm yellow laser. The 4 nJ pulses as short as 42 fs were obtained corresponding to a peak power of 100 kW. With the repetition rate of 104 MHz, the average power of 420 mW was attained. The time-bandwidth product of generated laser pulse was measured to be 0.324 with a beam quality factor of M2  ≤ 1.13. The exceptional performance of visible femtosecond laser may find potential applications in various fields...

We present design and performance data of an energy-scaled diode-pumped Alexandrite laser in single longitudinal mode operation developed as a beam source in a mobile general-purpose Doppler lidar. A maximum pulse energy in Q-switched operation of 4.6 mJ and a maximum average power of 2.7 W were achieved for a repetition rate range from 500 to 750 Hz with excellent beam quality of M 2 =1.1. Two rugged and compact demonstrator lasers were built and integrated into mobile lidar systems, where a bandwidth of approximately 3 MHz is measured...

The long-pulse alexandrite laser uses Cr3+ :BeAl2 O4 crystals as the activation medium and has a 755nm wavelength and millisecond pulse duration. The long-pulse alexandrite laser has been utilized for hair removal, vascular lesions, pigmented lesions, and other conditions because melanin and hemoglobin in the skin, subcutaneous tissues, and skin appendages can specifically absorb this type of laser. To serve as a guide and source of inspiration for the clinical use of this type of laser, we review the present research status and advancement of the long-pulse alexandrite laser in the treatment of the aforementioned categories of disorders...

BACKGROUND: Infantile hemangioma (IH) is a common vascular tumor in female infants, which can lead to aesthetic issues and facial scarring. This study aimed to investigate the inhibitory effects and underlying mechanisms of 755 nm long-pulsed alexandrite laser on IH. METHODS: Hemangioma endothelial cells (HemECs) were exposed to 755 nm long-pulsed alexandrite laser to evaluate its impact on cell proliferation and apoptosis. A patient-derived xenograft model was established to assess the inhibitory effects of laser treatment on IH in vivo...