A new method for the absolute measurement of reflectivity

1966 ◽  
Vol 35 (274) ◽  
pp. 861-866 ◽  
Author(s):  
P. M. D. Bradshaw ◽  
R. Phillips ◽  
R. A. Smith
Keyword(s):  
Light Beam ◽  
Normal Incidence ◽  
Absolute Measurement ◽  
New Method ◽  
Spectral Reflectivity ◽  
The Absolute

SummaryThe theory of a new method for the determination of reflectivity at truly normal incidence is described. A parallel light beam falls on the specimen after passing through a glass cube with semi-silvered diagonal mounted at the centre of an optical goniometer. The various reflected beams are measured by a photomultiplier fixed to the telescope of the goniometer. Experiment has proved the validity of the method and the spectral reflectivity of pyrite in air and in oil has been investigated.

Correlation Study between a New Interferometric Asphere Metrology System and Fizeau Interferometer

2007 ◽  
Vol 364-366 ◽  
pp. 1142-1146 ◽  
Author(s):  
Michael F. Kuechel ◽  
Daniel M. Sykora
Keyword(s):  
Classical Problem ◽  
Normal Incidence ◽  
Absolute Measurement ◽  
Correlation Study ◽  
New Method ◽  
Optical Systems ◽  
Production Environment ◽  
Aspheric Surfaces ◽  
Phase Measurements ◽  
Commercial System

Recent developments in next generation disc technology, cameras in mobile phones, zoom-lenses for small digital cameras and camcorders, digital SLRs, and television cameras have amplified the demand for affordable optical systems with outstanding image quality, a combination that can only be achieved using aspheric surfaces. The metrology of aspheric surfaces is a classical problem, but solutions so far have not fulfilled all demands for system cost, TACT (Total Average Cycle Time), minimized tooling, measurement uncertainty, spatial resolution, robustness in a production environment and many more. Zygo Corp. presents here a new method [1,2] for measurement of rotationally symmetrical aspheric surfaces using a new commercial system, which has the potential to fulfill these industry requirements. During measurement, the surface is scanned along its symmetry axis in a Fizeau cavity with a spherical reference surface. The coordinates x,y,z at the (moving) zone of normal incidence are derived from simultaneous phase-measurements at the apex and zone. Phase-shifting Fizeau interferometry and displacement interferometry are combined in the new commercial system to realize this new method. Aspheric departure from a best-fitsphere approaching 800 microns can be measured, and absolute measurement is possible with an absolutely calibrated transmission sphere. A custom parabolic artifact is measured with conventional null Fizeau interferometry and by the new commercial system. Data is reported for each technique along with a difference map achieved by fiducialized data subtract where 32.0 nm peak-to-valley (PV) and 3.6 nm R.M.S. are achieved.

A Method for Calculating the Index of Refraction of Thin Films

1975 ◽  
Vol 53 (18) ◽  
pp. 1737-1742 ◽  
Author(s):  
J. H. Wohlgemuth ◽  
D. E. Brodie
Keyword(s):  
Thin Films ◽  
Spectral Range ◽  
Variational Approach ◽  
Accurate Determination ◽  
Normal Incidence ◽  
Index Of Refraction ◽  
New Method ◽  
Reflection And Transmission ◽  
Transmission Measurements

A new method for determining the index of refraction from normal incidence reflection and transmission measurements has been developed. Several other methods are reviewed to explain why a new method is needed. The author's method used a thickness variational approach. For an accurate determination of n and k, the method requires normal incidence reflection and transmission measurements over a fairly broad spectral range for at least two different film thicknesses. These requirements are unavoidable for normal incidence methods.

Novel Experimental Technique for the Absolute Determination of Quantum Yields

1998 ◽  
Vol 52 (8) ◽  
pp. 1103-1110
Author(s):  
G. Kaindl ◽  
R. Weger ◽  
P. Bajons
Keyword(s):  
Quantum Yield ◽  
Light Emission ◽  
Practical Method ◽  
New Method ◽  
Quantum Yields ◽  
Absolute Determination ◽  
Exciting Wavelength ◽  
Fluorescence Light ◽  
The Absolute

A new method for the absolute determination of the quantum yield based on the trapping of fluorescence light within a cylinder is discussed. First the trapping probability of photons—which are emitted in transparent rods or fluid-filled tubes—is investigated theoretically. The studies are based on the extension of light governed by the laws of reflection and refraction. The effect of nonhomogeneous distribution of the centers of fluorescence light emission on the calculation procedures is taken into account. Then the adaptation of the theoretical results to a new practical method is shown. The quantum yield as a function of the exciting wavelength is determined in one experimental cycle. The discussion of the method is performed by measurements on fluorescein in aqueous solution. The results are compared to literature data. The conformity demonstrates the applicability of the new method.

scholarly journals A new method of determining the radiation constant

1912 ◽  
Vol 86 (585) ◽  
pp. 180-196 ◽  
Keyword(s):  
Black Body ◽  
Absolute Temperature ◽  
Absolute Zero ◽  
New Method ◽  
Platinum Black ◽  
Main Current ◽  
First Case ◽  
Black Surface ◽  
The Absolute

According to stefan's law the rate of radiation of energy from a full radiator in surroundings at a temperature of absolute zero is σ θ 4 ergs per cm. 2 per sec., where θ is the absolute temperature of the radiator. If the radiator be in surroundings which are themselves full radiators, but at absolute temperature θ 1 , the rate of loss of energy by radiation is taken to be σ( θ 4 - θ 1 4 ). The classical determination of the constant σ is due to Kurlbaum, who used a surface bolometer with a platinum-black surface. The rise of temperature of the bolometer when exposed to the radiation from an approximately full radiator or "black body" was observed. The radiation was then cut off, and an equal rise of temperature was produced by increasing the main current in the bolometer. It was assumed that the energy received per second from the radiator in the first case was equal to the energy received per second from the increase of current in the second ease. The resulting value of σ was 5·33 x 10 -5 ergs per cm. 2 per sec. per deg. 4 , or 5·33 x 10 -12 watts per cm. 2 per deg. 4 .

Sign in / Sign up

Export Citation Format

Share Document