Continuous-wave, single-frequency 229 nm laser source for laser cooling of cadmium atoms.

Continuous-wave output at 229 nm for the application of laser cooling of Cd atoms was generated by the fourth harmonic using two successive second-harmonic generation stages. Employing a single-frequency optically pumped semiconductor laser as a fundamental source, 0.56 W of output at 229 nm was observed with a 10-mm long, Brewster-cut BBO crystal in an external cavity with 1.62 W of 458 nm input. Conversion efficiency from 458 nm to 229 nm was more than 34%. By applying a tapered amplifier (TA) as a fundamental source, we demonstrated magneto-optical trapping of all stable Cd isotopes including isotopes Cd111 and Cd113, which are applicable to optical lattice clocks.

Injection-locked operation of an optically pumped semiconductor laser.

We demonstrate a single-frequency, continuous-wave, optically pumped semiconductor laser (OPSL) using an injection-locking technique. Parameters such as output coupling, injection power, and injection wavelength are investigated. With the proper parameters, the output power of the injection-locked laser exceeds the output power of its free-running condition. With 1.5 W of injection power from the master laser, over 9 W of output power is achieved at 1015 nm.

Continuous-wave all-solid-state 244 nm deep-ultraviolet laser source by fourth-harmonic generation of an optically pumped semiconductor laser using CsLiB6O10 in an external resonator.

We report an all-solid-state laser system that generates over 200 mW cw at 244 nm. An optically pumped semiconductor laser is internally frequency doubled to 488 nm. The 488 nm output is coupled to an external resonator, where it is converted to 244 nm using a CsLiB(6)O(10) (CLBO) crystal. The output power is limited by the available power at 488 nm, and no noticeable degradation in output power was observed over a period of several hours.

Electrosurgical facial resurfacing: a prospective multicenter study of efficacy and safety.

BACKGROUND: A novel electrosurgical technology that uses a bipolar electrode-tipped stylet to deliver relatively low-radiofrequency energy through an electrically conductive medium has been developed. OBJECTIVE: To evaluate the efficacy and safety of the radiofrequency resurfacing system for the treatment of facial wrinkles. DESIGN: Multicenter, prospective, noncomparative study with longitudinal follow-up. SETTING: Four US academic dermatologic surgery clinics. PATIENTS: Ninety-five patients with mild to severe photodamage (Fitzpatrick classes I-III) involving periorbital (75 treatment sites) and perioral (50 sites) facial skin. INTERVENTION: Radiofrequency resurfacing with the use of 2 to 3 passes at 125 or 139 V. MAIN OUTCOME MEASURES: Wrinkle and cosmetic improvements evaluated by patients, investigators, and, by means of photographs, an independent panel of 5 evaluators. RESULTS: All evaluators determined a positive mean improvement in wrinkles for both periorbital and perioral anatomic sites, with greater improvement for patients with more severe wrinkles at baseline. An increased number of passes and higher voltage settings had a positive impact on wrinkle improvement. Transient postinflammatory hyperpigmentation occurred in 26% of periorbital and 4% of perioral sites. Hypertrophic scars occurred in 3.8% of treatment sites, with all but 1 scar resolving by 6 months. For the most part, healing was rapid, pain was minimal, and erythema largely resolved within 2 months. Other untoward effects were relatively few and short-lived. CONCLUSIONS: At the study settings used, radiofrequency resurfacing is an effective modality in the treatment of periorbital and perioral wrinkles in patients with Fitzpatrick class I, II, and III photodamage. There is less severe postoperative morbidity than seen with carbon dioxide or coagulating erbium:YAG lasers. The potential risks are similar to those seen with other resurfacing modalities.

Dermabrasion for prophylaxis and treatment of actinic keratoses.

BACKGROUND: After dermabrasion, patients with actinic keratoses remain free of new lesions for many years. This clinical effect has been alluded to for 40 years in the dermatologic literature. However, there has been no consensus on how long this clinical benefit actually lasts. OBJECTIVE: To ascertain the longevity of the beneficial effect of dermabrasion, clinical records of patients who underwent this procedure for treatment of actinic keratosis were reviewed. METHOD: Retrospective review. RESULTS: A total of 23 such patients with at least 2 years good clinical follow-up were identified. Their ages ranged from 33 to 76 years. One year after dermabrasion, 96% remained free of new actinic keratoses. The benefits of dermabrasion gradually diminished with 83% clear at 2 years, 79% at 3 years, 64% at 4 years, and 54% at 5 years. The average time after dermabrasion before the appearance of one actinic keratoses was 4 years (median, 4.5 years). Dermabrasion, however did not prevent the appearance of basal cell carcinomas in the perinasal area. CONCLUSION: Dermabrasion provides long-term effective prophylaxis against actinic keratoses and presumably squamous cell carcinomas. The benefits last for an average of 4 years before even one new actinic keratosis reappears. Cryosurgery, 5-Fluorouracil, and chemical peels result in much shorter prophylaxis. Dermabrasion is the most effective modality for prevention of new actinic keratoses.

Dermabrasion of the hyperkeratotic foot.

BACKGROUND: Keratoderma is a common problem. Its treatment is difficult and may be associated with systemic side effects. OBJECTIVE AND METHOD: To describe the use of dermabrasion for hyperkeratotic conditions of the palms and soles. RESULTS: Dermabrasion of keratoderma is an easy, quick, and safe method that brings immediate relief to patients, allows improved penetration of topical medications, and facilitates the control of the underlying disease with simple measures. CONCLUSIONS: Dermabrasion should be considered among the treatment options for keratoderma.

Erbium:YAG laser photothermal retinal ablation in enucleated rabbit eyes.

The erbium:YAG laser has been shown to produce precise tissue ablation because of the high water absorption of the 2.94-microns wave-length emitted by this laser. We used an experimental system to create lesions of various depths in the surface of the rabbit retina in enucleated eyes in vitro to examine the potential application to maneuvers such as retinotomy and the removal of epiretinal membranes in vitrectomy. With an air/retinal interface, single pulses produced discrete craters in the retinal surface with a depth proportional to fluence, ranging from 30 microns for a pulse of 1.3 J/cm2 to a full-thickness retinotomy at 3.9 J/cm2. An adjacent zone of coagulated tissue ranging in size from 15 to 40 microns was noted. Multiple pulses had an additive effect. With a fluid/retinal interface, 20 pulses of 3.6 J/cm2 produced a full-thickness retinotomy, with an adjacent zone of damaged tissue up to 1 mm, caused by effects of volatilization of intervening fluid. The erbium:YAG laser may have a role in vitreoretinal surgery.

Ablation of facial scars by programmed dermabrasion.

Revisions of scars, characteristically deferred for 6 to 12 months after wounds have healed, are performed to improve function and appearance. However, none of the techniques that has evolved to modify cicatrical deformities has afforded total, permanent effacement of scars already present. Evidence is presented here that dermabrasion of both surgical and accidental scars of the face, done 4 to 8 weeks after the primary wound, usually eliminates visible residual cicatrization.

Dermabrasion by wire brush.

While many physicians choose the fraise for all dermabrasive surgery, others prefer the faster abrasiveness and reduced friction of the brush for deep full-faced abrasions, removal of tattoos, and revision of scars. In addition to preoperative preparation and postoperative care of the patient, the author's technique for full-face abrasion with the power-driven rotary brush is described.

The treatment of soft tissue defects with injectable collagen.

Two forms of highly purified bovine dermal collagen (Zyderm I and II Collagen Implant) are currently in widespread clinical use for the treatment of dermal soft tissue defects. These materials, which closely resemble human collagen, are administered via injection in a series of outpatient treatments. With successive injections, small amounts of collagen are deposited to fill areas deficient in soft tissue. A review of the literature indicates that these materials can be used safely and effectively to correct certain scars, age-related wrinkles, areas of steroid atrophy, and small surgical defects.