High precision damage-resistant multiple-pass ultraviolet reflectometer
A multiple-pass cell was reported by John White in 1942. Since them, it has been adapted for use as a high-precision reflectometer. The multiple-pass reflectometer has been studied and reported by Arnon and Baumeister. Here, a reflectometer which is similar is described. It utilizes a uv laser operating at lambda = 351 nm as the source and the White-cell mirrors are high-reflection dielectric coatings designed for that wavelength. Because of the low-loss reflectors used in the cell, a high number of traversals, reflections, can be achieved; R greater than or equal to 239. The use of dielectric mirrors also improves the damage resistance of the apparatus which is important when a uv laser beam is used. The results of reflectance measurements performed on several ultraviolet high reflectors are also reported. These include conventional dielectric coatings as well as a hybrid coating consisting of Al/sub 2/O/sub 3/, HfO/sub 2/, and SiO/sub 2/ layers. The Los Alamos optical damage laboratory has observed and defined several types of laser-induced damage to optical materials. In the case of high reflection, multi-layer, dielectric coatings, damage may be defined as any change in the coating layers or at the substrate interface which causes a measurable change in reflectance at its design wavelength. Since most dielectric high reflectors have reflectances approaching unity, and a change caused by laser irradiation can be minute, a precise method for measuring high reflectance must be utilized. A multiple-pass reflectometer based on the White cell was selected because of its demonstratd precision and high accuracy. It utilizes a laser as the source for reasons described later.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6461712
- Report Number(s):
- LA-UR-85-3734; CONF-8410186-5; ON: DE86002443
- Resource Relation:
- Conference: Symposium on optical materials for high power lasers, Boulder, CO, USA, 15 Oct 1984; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
47 OTHER INSTRUMENTATION
REFLECTIVE COATINGS
DIELECTRIC PROPERTIES
REFLECTIVITY
MEASURING METHODS
DESIGN
MATHEMATICAL MODELS
ULTRAVIOLET RADIATION
COATINGS
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SURFACE PROPERTIES
420300* - Engineering- Lasers- (-1989)
440300 - Miscellaneous Instruments- (-1989)