Showing papers on "Ruby laser published in 2000"

Ruby laser hair removal: evaluation of long-term efficacy and side effects

Abstract: Background and Objective: Although several studies on laser-assisted hair removal have been published, data on long-term follow-up are few. The present study investigated the long-term efficacy and safety of normal-mode ruby laser pulses on hair removal. Study Design/Materials and Methods: The normal-mode ruby laser (Epilaser; 694 nm, 3 msec) was used to treat a wide range of body sites in 51 volunteers. The mean follow-up after the last treatment was 8.37 months. Results: Sixty-three percent of the patients had sparse regrowth. The mean fluence used was 46.5 J/cm 2 in patients who had sparse hair regrowth and 39.3 J/cm 2 in patients who had moderate hair regrowth (P = 0.0127). Transient pigmentary changes occurred most frequently in patients with skin type 4. Conclusion: The normal-mode ruby laser is an efficient and safe method for long-term hair reduction, especially in fair-skinned individuals with dark hair. Higher fluences produce greater long-term efficacy. Adverse effects are minimal and transient. Lasers Surg. Med. 26:177‐ 185, 2000. © 2000 Wiley-Liss, Inc.

Successful treatment of treatment‐resistant laser‐induced pigment darkening of a cosmetic tattoo

Abstract: Background and Objective Cosmetic tattoo removal has a reported risk of immediate pigment darkening when treated with a high energy, nanosecond pulsed-laser system. Surgical treatment options for this reaction are limited and carry significant risk of scarring and permanent pigment alterations. This report describes the response of a resistant Q-switched ruby laser-induced cosmetic tattoo ink darkening to multiple treatments with the Q-switched alexandrite laser and Q-switch Nd:YAG laser and textural improvement with the UltraPulse CO2 laser. Study Design/Materials and Methods A woman with Q-switched ruby laser-induced pigment darkening of a cosmetic tattoo of the upper lip resistant to four further treatments with the ruby laser and two chemical peels received a total of 26 treatments with the Q-switched alexandrite and Nd:YAG lasers and a single treatment with the UltraPulse CO2 laser, most treatments being done at monthly intervals. Results Treatment of the affected areas with the Q-switched alexandrite and Nd:YAG lasers resulted in complete clearing of the pigment without scarring, but revealed some preexisting textural changes. Use of the UltraPulse CO2 laser smoothed the surface irregularities. Conclusion The Q-switched pigment lasers are a useful modality for treating this pigment darkening reaction. As in this case, multiple treatment sessions with the laser may be necessary but the pigment can be expected to clear eventually without scarring. Any textural changes may be blended with the UltraPulse CO2 laser with further improvement. Lasers Surg. Med. 27:358–361, 2000. © 2000 Wiley-Liss; Inc.

Hair reduction using a new intense pulsed light irradiator and a normal mode ruby laser.

Abstract: OBJECTIVE : The main purpose of this clinical study was to compare the effectiveness of an intense pulsed light irradiator system (IPL) and a normal mode ruby laser for hair removal. MATERIALS AND METHODS : Thirty-one patients were treated 3 times with a new IPL system on one side of the chin and neck and with a normal mode ruby laser on the other side. After 6 months, nine of the patients received 3 additional IPL treatments and 11 patients received 3 additional ruby laser treatments. All treatment intervals were 2 months. Hair reduction was measured by hair counts on close-up photographs. RESULTS : Hair reduction was obtained by 93.5% of the patients after 3 IPL treatments and by 54.8% after 3 ruby laser treatments. The average hair count was reduced by 49.3% after IPL treatments and by 21.3% after ruby laser treatments. Three additional IPL treatments following 3 IPL treatments resulted in only 6.6% further hair reduction - in total 55.9%, whereas 3 IPL treatments following 3 ruby laser treatments resu...

Q-Switched Ruby Laser Treatment for Postsclerotherapy Hyperpigmentation

Abstract: Background.One of the most common adverse sequelae of sclerotherapy is cutaneous hyperpigmentation.Objective.We used the Q-switched ruby laser to treat postsclerotherapy hyperpigmentation.Methods.Eight patients developed pigmentation lasting more than 1 year (1–2 years on average) after sclerotherap

Hair Removal Using a 5‐msec Long‐Pulsed Ruby Laser

Abstract: Background.Unwanted hair is a widespread cosmetic problem. Many temporary methods of hair removal exist, with laser hair removal rapidly becoming the most widely used modality.Objectives.Our objective was to evaluate the efficacy and side effects of a long-pulsed ruby laser for epilation in patients

Reduction of regrowing hair shaft size and pigmentation after ruby and diode laser treatment.

Abstract: Laser pulses which selectively damage pigmented hair follicles are a useful treatment for hypertrichosis. Clinically, regrowing hairs are often thinner and lighter after treatment. In this study, hair shaft diameter and optical transmission (700 nm) were measured before and after ruby (694 nm) and diode (800 nm) laser irradiation. Hair was collected from 47 and 41 subjects treated with ruby (0.3 ms and 3 ms) and diode (10-20 ms) lasers, respectively. Responders were defined as subjects with significant long-term hair loss as determined by hair counts at 9 and/or 12 months after treatment. In ruby laser responders (34/47), regrowing hairs were significantly both thinner (decreased diameter) and lighter (increased transmission). In nonresponders (13/47), regrowing hairs were lighter, but not thinner. The regrowing hair shaft absorption coefficient (as calculated assuming Beer's law) was significantly decreased by 0.3 ms ruby laser treatment, but was not changed by 3 ms ruby laser or diode laser treatment. After diode laser treatment, 38 of the 41 subjects were responders and regrowing hairs were both thinner and lighter. These results show that laser treatments can affect structural recovery (size of hair), follicular pigmentation (hair absorption coefficient), or both. Regrowth of thinner hair (decreased shaft diameter) occurs in conjunction with actual loss of hair. After long pulses (3 ms ruby; diode), regrowing hair was thinner and also lighter to an extent related to the decrease in hair diameter. In contrast, short ruby laser pulses (0.3 ms) appeared to be capable of inhibiting follicular pigmentation per se, in addition to affecting the hair diameter. This may account for the complete regrowth of lighter hair in nonresponders treated with 0.3 ms pulses. Laser-induced reduction in hair diameter and/or pigmentation are both long-term responses which confer cosmetic benefits in addition to actual hair loss.

Efficacy, tolerability, and safety of a long-pulsed ruby laser system in the removal of unwanted hair.

Abstract: Background. Unwanted hair growth is a common, usually physiologic phenomenon. Objective. In this study the efficacy and tolerability of a long-pulsed ruby laser system was compared with needle electrolysis and hot wax on three parts of the body. Methods. Thirty volunteers were treated three times on the forearm (n = 10), on the face (n = 10), or in the pubic area (n = 10) with 25 J/cm2 laser, 40 J/cm2 laser, needle electrolysis, and hot wax therapy. Results. The 25 J/cm2 and 40 J/cm2 laser treated sites showed a statistically significant decrease (38% and 49%, respectively) in the number of hairs at the first visit after the last treatment compared to the pretreatment hair counts. No significant decrease was observed in the needle electrolysis and hot wax treated sites. Laser therapy yielded better results on the forearm than on the face or pubic area and was scored as the least painful. Conclusion. The long-pulsed ruby laser is a promising, well-tolerated method of epilation.

Dark skin tissue reaction in laser assisted hair removal with a long-pulse ruby laser.

Abstract: BACKGROUND: Photo-epilation has become an accepted modality for the removal of unwanted hair. However, adverse effects may occur in darker skin patients. Treatment with the ruby laser is generally advised for skin types I-III. Treatment of over 3000 patients (skin types I-III) in our clinic has resulted in a minimal percentage (approximately 3%) of adverse effects. Increasing pulse duration should allow the epidermis to cool and thus minimize thermal damage so that treatment can be extended to dark skin patients. OBJECTIVES: The purpose of our study was to compare tissue reaction in dark skin patients (skin type IV) after treatment with a long-pulse (20 msec) ruby laser and compare the reaction with a 1 msec ruby laser treatment. RESULTS: Hair removal efficacy was determined to be similar with both pulse durations, but tissue reaction was more severe, including eschar and hypo-pigmentation, following treatment of dark skin patients with the 1 msec protocol. Increasing the pulse duration to 20 msec appears...

Successful removal by ruby laser of darkened ink after ruby laser treatment of mismatched tattoos for acne scars.

Abstract: Cosmetic tattoos are becoming increasingly popular. Elimination of cosmetic tattoos is sought because of misplacement or migration of tattoo pigment, allergic reactions to the various pigments or dissatisfaction of the customer for various reasons. Removal of unwanted pigment is a domain of laser surgery using various Q-switched laser systems, such as the ruby, alexandrite, pulsed dye and Nd:YAG lasers. Dark colours are easily removed by these lasers, whereas red, pink and skin-toned pigment may turn black if exposed to Q-switched laser light. This ink-blackening occurs because Q-switched lasers heat up the pigments, which consist of ferric oxide, and reduce them into ferrous oxide, which is black. Laser-induced black ink is not always readily removed. A successful ruby laser-removal of laser-induced blackened cosmetic tattoos for acne scar camouflage is reported. The advantageous outcome in this case contrasts with other published cases where laser-darkened pigment had to be removed by other measures, or was permanent. Test site treatment can limit the problem to some degree but, in addition to test-treating, some kind of 'tattoo identification card' could help to prevent problems in this field and allow 'in vitro' test treatment.

A review of the ruby laser with reference to hair depilation.

Abstract: There is a clinical need in the fields of reconstructive and cosmetic plastic surgery for a safe, simple, and effective method of hair depilation. Depilatory clinics have been established throughout the country, commonly using the ruby laser, to treat a cohort of the population, estimated to be between 6% and 10%, recognized as being hirsute. Clinical trials performed to date have not established a protocol that suits the previously mentioned criteria and have been, usually, small in number and short in follow-up. With the increased use that this form of laser treatment will inevitably undergo, it is the belief of the authors that the only way of ascertaining whether the treatment is safe, simple, and effective is first to establish how the ruby laser works. This review relates the knowledge that is currently available regarding the function of the ruby laser to a number of the clinical studies that have been undertaken, including three that have used other types of laser. Using this information, future areas in which research is required can be defined, ultimately to improve the clinical efficacy of ruby laser-assisted hair removal while lessening the current side effects (namely, superficial burning, and hypo- and hyperpigmentation).

Plasma dynamics from laser ablated solid lithium

Abstract: Emission plasma plume generated by pulsed laser ablation of a lithium solid target by a ruby laser (694 nm, 20 ns, 3 J) was subjected to optical emission spectroscopy: time and space resolved optical emission was characterised as a function of distance from the target surface. Propagation of the plume was studied through ambient background of argon gas. Spectroscopic observations can, in general, be used to analyse plume structure with respect to an appropriate theoretical plasma model. The plume expansion dynamics in this case could be explained through a shock wave propagation model wherein, the experimental observations made were seen to fit well with the theoretical predictions. Spectral information derived from measurement of peak intensity and line width determined the parameters, electron temperature (T e) and electron number density (n e), typically used to characterise laser produced plasma plume emission. These measurements were also used to validate the assumptions underlying the local thermodynamic equilibrium (LTE) model, invoked for the high density laser plasma under study. Some interesting results pertaining to the analysis of plume structure and spatio-temporal behaviour of T e and n e along the plume length will be presented and discussed.

Modern physical principles of laser ablation

Abstract: Physical principles of ablation, that is a phenomenon of fast superficial evaporation of the solid or liquid due to energy deposition into a thin layer near a surface of the specimen, are discussed. The opportunity of studying ablation at a laboratory is directly related to invention of a laser, which is very intensive source of radiation energy. For the first time, the laser ablation was demonstrated by Maiman in 1960 just by using his ruby laser for perforation of a razor blade. Since then there has been demonstrated, that the laser ablation has very complicated physics and can be used for a lot of applications. This fact results from a tremendous variety of laser parameters. Variations of laser intensity in time, radiation spectrum, geometry of specimen irradiation, its chemical composition, etc., result in unique possibility of changing physical parameters of ablation and, hence, its physical features, which allow us to use laser radiation both in science and technology beginning from laser material processing up to high-temperature plasma formation for laser fusion.

Dynamic ballistic impact events imaged at 500 kHz using laser-based image acquisition

Abstract: An integrated, high-speed photographic system combining a high-repetition rate, pulsed ruby laser and a high-framing rate CCD camera has been demonstrated. Individually, the laser and camera have been discussed previously and each was developed under the Small Business Innovative Research sponsorship through the Air Force Research Lab. This paper present for the first met digital images of dynamic ballistic events captured at 500 kHz using the two elements integrated as a high-speed digital imaging system.

Color holography: present state of the research activities at ISL

Abstract: Some experiments concerning color holography and color holographic interferometry have been conducted at ISL. In a first stage, static holograms have been recorded with c.w. lasers in PFG-03C silver-halide panchromatic holographic plates. Color holographic interferometry is at present experimented and developed. Quantitative measurements by double-exposure holography are not possible. An example, on a cantilever plate, showing the achromatic fringe, is visualized on the reconstructed image. Quantitative deformations of the plate are presented. An experimental set-up designed for the real-time holographic interferometry of phase objects is also presented. A video film, recorded at 25 frames per second and relating laboratory experiments on some fluid mechanics flows, is shown. New difficulties occur when these experiments are carried out by using pulsed lasers. Our first tests on this technique are presented. Three pulsed lasers have been used: a ruby laser, a frequency doubled YAG laser and a frequency doubled titanium-sapphire laser. Ruby and YAG lasers, delivering red and green waves, are commercially available. A special frequency doubled titanium-sapphire laser, built as ISL produces the blue line. Preliminary results are presented and discussed.

Cr: YSO saturable absorber for the three-level Cr:BeAl2O4 laser at 680.4 nm

Abstract: In addition to being an efficient saturable absorber Q switch for the tunable Cr:BeAl2O4 laser for its entire tuning range from 700 to 818 nm, the Cr:YSO is shown to be an effective saturable absorber Q switch for the 3-level Cr:BeAl2O4 laser at 680.4 nm. The passive Q-switching performance of this 3-level laser is similar to that of the passively Q-switched ruby laser.

Intracorporeal holmium:yag laser lithotripsy - current stage

Abstract: Since Mulvany and Beck first description of Ruby laser for lithotripsy, urologists have been exploiting every possible application of this technology. Relevant to urology is the recently developed Holmium:YAG laser with both soft tissue and lithotripsy applications. The Holmium:YAG laser can effectively fragment calculi of all compositions mainly through a photothermal mechanism. This mechanism result in fewer migrated and smaller stone fragments, compared to electrohydraulic lithotripsy, mechanical lithotripsy or pulsed dye lasers. Because the Holmium:YAG laser can be carried through small flexible quartz fibers, it is ideally suited for the use through small-diameter flexible ureteroscopes in the upper urinary tract. We here provide a comprehensive revision of basic concepts as wavelength, absorption coefficient, chromophores, pulsed laser and the photothermal mechanism of the Holmium:YAG laser lithotripsy. Security concerns, the impact of energy and frequency settings, as well as the influence of different fiber types and its diameters on stone fragmentation are analyzed. The clinical Holmium: YAG laser lithotripsy applications and the series reporting their use are reviewed.

Lasers of dermatology

Abstract: 1 The Basic Science of Laser-Tissue Interactions in Dermatology.- Laser Radiation.- Laser Construction.- Laser Light Delivery.- Terminology.- Spatial Average Energy Fluence.- Number of Passes.- Laser-Tissue Interactions.- Photothermal Interactions.- Selective Photothermolysis.- Further Reading.- 2 The Safe Use of Lasers in Dermatology.- Classification of Lasers.- Warning Signs for Laser Equipment.- Environmental Considerations for the Safe Use of Lasers in Dermatology.- Local Rules.- Laser Controlled Area.- Fire, Ignition and Electrical Hazards.- Ocular Hazards.- Hazards of the Laser Plume.- Laser Training.- Core of Knowledge.- Laser Safety Education Program.- Clinical Training.- References and Further Reading.- 3 Laser Treatment of Cutaneous Vascular Lesions.- Treatment of Port Wine Stains.- Principles of Selective Photothermolysis and the Treatment of Port Wine Stains.- Port Wine Stain Treatment with the Flashlamp Pulsed Dye Laser.- Side Effects from Pulsed Dye Laser Therapy.- Psychological Aspects of Port Wine Stain Treatment.- Argon Laser Treatment of Port Wine Stains.- Continuous Wave Dye Laser Treatment of Port Wine Stains.- Robotic Scanning Handpieces.- Copper Vapour Laser Treatment of Port Wine Stains.- Nd:YAG Laser Treatment of Port Wine Stains.- Krypton Laser.- CO2 Laser Treatment of Port Wine Stains.- Laser Treatment of Capillary (Strawberry) Haemangiomas.- Laser Treatment of Leg Veins and Telangiectasias.- Treatment of Other Cutaneous Vascular Lesions.- Laser Treatment of Scars and Striae.- Laser Treatment of Striae Distensae.- Pulsed Dye Laser Treatment of Psoriasis.- Laser Treatment of Viral Warts.- References and Further Reading.- 4 Laser Treatment of Pigmented Lesions.- Categories of Pigmented Lesions.- Pulsed Dye Laser (510 nm) Treatment of Pigmented Lesions.- Q-Switched Ruby Laser Treatment of Pigmented Lesions.- Q-Switched Nd:YAG Laser Treatment of Pigmented Lesions.- Q-Switched Alexandrite Laser Treatment of Pigmented Lesions.- Copper Vapour Laser Treatment of Pigmented Lesions.- Other Lasers for the Treatment of Pigmented Lesions.- Treatment of Melanocytic Naevi with Lasers.- References and Further Reading.- 5 Laser Treatment of Tattoos.- Q-Switched Ruby Laser Treatment of Tattoos.- Q-Switched Nd:YAG Laser Treatment of Tattoos.- Q-Switched Alexandrite Laser Treatment of Tattoos.- Pulsed Dye (510 nm) Laser Treatment of Tattoos.- Comparative Studies of Lasers Used to Remove Decorative Tattoos.- Laser Treatment of Other Tattoos.- Cosmetic Tattoos.- Traumatic Tattoos.- References and Further Reading.- 6 The Carbon Dioxide and Erbium:YAG Lasers in Dermatology.- CO2Laser Treatment in Dermatology.- Incisional Surgery with the CO2 Laser.- Wound Healing with CO2 Laser Excisions.- Pulsed, Superpulsed and Scanned CO2 Lasers.- Tissue Ablation with the CO2 Laser.- Resurfacing Skin with the CO2 Laser.- Mechanism of Action.- Preoperative Patient Evaluation and Preparation.- Treatment Methods.- General Considerations.- Coherent UltraPulse.- Sharplan SilkTouch/Feather Touch.- Other CO2 Lasers.- Postoperative Management.- Complications of Resurfacing with the CO2 Laser.- Long-Term Results of CO2 Laser Resurfacing.- Comparison Between CO2 Laser Resurfacing and Chemical Peels.- CO2 Resurfacing of the Acne-Scarred Face.- Erbium:YAG Laser Treatment in Dermatology.- Clinical Studies with the Er:YAG Laser.- Comparisons and Combinations of the Er:YAG and CO2 Lasers.- Conclusions.- References and Further Reading.- 7 Hair Removal by Lasers.- Laser Removal of Hair by Selective Photothermolysis.- Ruby Laser Treatment of Hair.- Alexandrite Laser Treatment of Hair.- Diode Laser Treatment of Hair.- Other Laser Treatments for Hair Removal.- Intense Pulsed Light Laser Treatment of Hair.- Treatment Techniques for Selective Photothermolysis of Hair.- Conclusions.- Laser-Assisted Hair Transplantation.- References and Further Reading.- 8 Photodynamic Therapy in Dermatology.- Systemic Photodynamic Therapy.- Clinical Studies.- Invasive Squamous Cell Carcinoma.- Bowen's Disease.- Malignant Melanoma.- Kaposi's Sarcoma.- Topical Photodynamic Therapy.- Light Sources.- Treatment of Cutaneous Malignancies with Topical Photodynamic Therapy.- Basal Cell Carcinoma.- Actinic Keratoses.- Bowen's Disease.- Squamous Cell Carcinoma.- Mycosis Fungoides.- Photodynamic Therapy for Benign Skin Disease.- References and Further Reading.- 9 New Lasers, Emerging Technology, Experimental and Developing Applications.- Diode Lasers.- Clinical Use in Dermatology.- Excimer Lasers.- Intense Pulsed Light Source.- Non-Ablative Cutaneous Laser Resurfacing.- Conclusions.- References and Further Reading.- Appendix: Index of Laser Manufacturers.

Structural studies of disperse crude-oil systems by small-angle X-ray scattering subjected to millisecond laser pulses

Abstract: The core size of complex structural units (CSUs) in paraffin crude oil was found by small-angle X-ray scattering. A variation of the core size with the energy and the number of millisecond pulses from a ruby laser was investigated.

Absorption spectra and selective excitation of Y3Al5O12 : Tm3+ and YLiF4 : Tm3+ laser systems

Abstract: The absorption spectrum and the Stark structure are measured for the first time at the temperature T = 300 K for high-lying 3 F 4 , 3 F 3 , 3 F 2 , 1 G 4 , 1 D 2 , 1 I 6 , 3 P 0 , 3 P 1 , 3 P 2 multiplets of Tm 3+ ions in the YAG: Tm 3 laser system with a concentration of 2, 5, 10, 15, and 80% and for 1 I 6 , 3 P 0 , 3 P 1 , and 3 P 2 multiplets in the YLiF 4 : Tm 3+ matrix with a concentration of 1%. It is demonstrated that, in the pulse-periodic regime of excitation, transmission and absorption coefficients of laser crystals depend on the relation of the time interval between the pulses (ΔT) and the lifetime τ of the metastable activator level if ΔT « τ. The investigation of absorption spectra of crystals with different concentrations of Tm 3+ has shown that, for excitation rates of active centers equal to 10 7 and 10 5 s -1 , two photons are sequentially absorbed through the 3 H 6 → 3 F 3 → 1 D 2 and 3 H 6 → 1 G 4 → 3 P 2 schemes. Analysis of the transmission coefficient I/I 0 of the YAG: Tin 3+ (2%) crystal as a function of the laser intensity of a free-running ruby laser reveals the appearance of induced emission from the 1 D 2 level in the process of excitation.

Laser-induced structure defects and their use for modification of properties of (Cd,Hg)Te epitaxial layers end CdTe cyrstals

Abstract: This Paper examines the experimental researches of structural defect generation in (Cd,Hg)Te epitaxial layers on CdTe substrates and CdTe mono-crystals after pulse laser treatment and the influence of these defects on mechanical, optical and galvano-magnetic properties of the samples. In the experiments we used the ruby laser radiation with energy density changed in the range 1,5-15 J/cm 2 . The duration of laser pulses (τ) was about 1,5 ms. Changes in the chemical composition of the irradiated surface have been analyzed by the Auger electron spectroscopy. The zones with increased defect concentration were determined by the method of the selective chemical etching. It has been determined that the pulse laser processing results in both the essential redistribution of the component concentration and generation of the point and extended defects in near-surface crystal layers excited by laser irradiation. After the laser irradiation of the samples the redistribution of the intensity of the luminescence bands and emergence of a new band were observed over the band 840 nm at the temperature of samples about 4,2 K. The essential growth of the spectral band intensity with a maximum within the band 875-885 nm at T= 77 K has been observed as well.

Combination of pulsed digital holography and laser vibrometry for the 3D measurements of vibrating objects

Abstract: An optoelectronic system is presented that is used to measure the 3D vector components of a vibrating object. The complete determination of the vibration occurs by combination of three different measurements. (1) A 3D system based on digital holography for the measurement of the 3D deformation vector along the directions x, y and z is used. Pulses from a ruby laser, with a separation in the range from 1 to 1000 microseconds, are used to record holograms on CCD sensors, which are later digitally reconstructed. (2) The shape of the object is determined. In this case too the ruby laser is used as a light source but now two pulses are emitted with different wavelengths. The wavelength change is produced by changing the distance between the plates of the laser output etalon. The shape is obtained by subtraction of the phases of the wavefronts recorded at the two different wavelengths. (3) For the absolute measurement of a vibration using double exposure holographic techniques, it is necessary to have a reference point where the absolute vibration is known. A precise measurement of the vibrations in a point is done by using a 3D laser Doppler vibrometer.

A Multipass System for Thomson Scattering Diagnostic with Multipulse-Lasing

Abstract: A Thomson scattering system with multipasses was set up for diagnostics on the tokamak NOVA-UNICAMP. As the laser beam comes back to the ruby laser operating in Q-switched mode, we observed the presence of multipulses, increasing the effective laser pulse energy by a factor of approximately 6.5 with operation at 18 passes. Much better results can be obtained by improving the quality of the optical surfaces. Measurements of the pulse characteristics and the results obtained are presented and discussed.

A Coherent Optical Technique Useful in Biomechanics: Holographic Interferometry

Abstract: The use of pulsed ruby lasers in recording holographic interferograms of specific surface displacements of the human body in vivo is demonstrated. Technical peculiarities of the technique are discussed and some practical examples shown.

Broadband Cr:YSO solid state saturable absorber for ruby, alexandrite, and Cr:LiCAF lasers: numerical study on passive Q-switching performance

Abstract: The Cr:YSO solid-state crystal has broad absorption bands in visible and near infrared spectral region. Although Cr:YSO was originally developed for laser applications, our experiments and numerical simulations show that it can act as an effective saturable absorber Q switch for the ruby laser at 694.3 nm, for the tunable alexandrite laser from 700 to 818 nm, and for the tunable Cr:LiCAF laser from 725 to 840 nm. Since the Cr:YSO is a robust solid-state crystal, the durable Cr:YSO Q-switched solid-state laser systems may find various practical applications. In this paper, theory of passive Q-switching with solid-state saturable absorber is briefly reviewed. Details of the numerical simulation for the passively Q-switched solid-state laser systems are presented.