Absolute reflectance

Absolute reflectance measurement for V-700 Series UV-visible and Near infrared NIR spectrophotometers

The absolute reflectance measurement system for the V-700 series UV-visible-NIR spectrophotometers is used to perform the measurement of the spectral properties, film thickness, angle variation or other characteristics of solid samples such as semiconductors, thin films and various optical elements.

ARV-913/ARN-914/ARN-915i/ARSV-916/ARSN-917/ARSN-918i/ARMV-919/ARMN-920/ARMN-921i

The absolute reflectance measurement accessories are designed to measure the absolute reflectance of a specular reflecting sample (metals or other materials) while varying the incidence angle (all models). The ARSV-916, ARSN-917, ARSN-918i, ARMV-919, ARMN-920 and ARMN-921i accessories also permit the transmittance measurement of a sample (without diffuse transmittance), while varying the incidence angle. Absolute reflectance and transmittance are measured by rotating the sample stage to determine the angle of the light incident to the sample and setting the detector in the path of the reflected light or the transmitted light through the sample.

Diffuse reflectance measurements can be obtained by mounting the sample at the rear of the integrating sphere with an incidence angle of 0º. Diffuse transmittance measurements can also be obtained by mounting the sample at the entrance of the integrating sphere with the sample holder at an incidence angle of 0º.

Effect of polarization when measuring absolute reflectance

Light from a spectrophotometer that employs a grating is always polarized. The ratio of the intensities of the S and P polarized light varies according to the wavelength and also differs from one grating to another for the same wavelength. The greater the angle of incidence of the beam on the sample, the greater the difference in the intensity of the S and P polarized reflected light making measurement inaccurate if the absolute reflectance is measured at a high angle of incidence. In this case, a polarizer can be set to 45 degrees so that the incident light can be considered non-polarized.

Range of Absolute Reflectance Measurement Accessories

Manual Measurement

ARV-913 Synchronous Absolute reflectance measurement accessory (UV-Vis). For use with V-750 and V-760

ARN-914 Synchronous Absolute reflectance measurement accessory (UV-Vis/NIR). For use with V-770 only

ARN-915i Synchronous Absolute reflectance measurement accessory (UV-Vis/NIR). For use with V-780 only

 

Reflectance measurement only
The incidence and collection angles are maintained with the same ‘synchronous’ angle by simultaneously rotating the sample stage and integrating sphere.

 

The ARV-913, ARN-914 and ARN-715i measure the absolute reflectance of a specular reflecting sample (metals, etc.) or the relative reflectance of a diffusely reflecting sample. It also permits the measurement of transmittance by using an optional solid sample holder for transmittance measurements. This attachment includes an integrating sphere with integrated detector(s). The angle of incidence of the sample is changed by moving the integrating sphere (in the measurement of absolute reflectance). The movable angular range of the integrating sphere is 5°to 90°(angle of incidence). The relative reflectance is measured by mounting the sample on the rear of the integrating sphere.

ARSV-916 Asynchronous Absolute reflectance measurement accessory (UV-Vis) For use with V-750 and V-760

ARSN-917 Asynchronous Absolute reflectance measurement accessory (UV-Vis/NIR) For use with V-770

ARSN-918i Asynchronous Absolute reflectance measurement accessory (UV-Vis/NIR) For use with V-780

Reflectance and transmittance measurement
The incidence and collection angles can be set independently in an asynchronous mode.

 

The ARSV-916, ARSN-917 and ARSN-918i manual absolute reflectance measurement accessories measure the absolute reflectance of a reflective sample or transmittance of a clear sample that does not diffuse light. The detector(s) is(are) equipped with an integrating sphere and also permits measurement of the relative reflectance and transmittance of samples that diffuse light (the sample holder for measurement of relative reflectance is standard, the sample holder for transmittance measurement is optional). Absolute reflectance and transmittance are measured by rotating the sample stage to determine the angle of the light incident upon the sample and setting the detector in the path of the reflected or transmitted light. The relative reflectance is measured with light normally incident to the sample, which is set behind the integrating sphere.

Automated measurement system

ARMV-919 Automated absolute reflectance measurement accessory (UV/VIS) For use with V-750 and V-760

ARMN-920 Automated absolute reflectance measurement accessory (UV/VIS/NIR) For use with V-770

ARMN-921i Automated absolute reflectance measurement accessory (UV/VIS/NIR) For use with V-780

Reflectance and transmittance measurement
The incidence and collection angles can be set independently in asynchronous mode.

 

The ARMV-919, ARMN-920 and ARMN-921i absolute reflectance measurement systems automate the measurement of spectral properties, including film thickness, angle variation or other characteristics of solid samples such as semiconductors, thin films and various optical elements. The incidence and collection angles can be set in a synchronous mode, simultaneously rotating the sample stage and integrating sphere. Alternatively, the incidence and collection angles can be set independently in asynchronous mode. The polarization properties of a sample can also be examined using P or S polarization or by setting the desired polarization angles.

Absolute Reflectance optical layout

Absolute Reflectance Measurement Accessories

Optional accessories

SSH-508 Solid Sample Holder

This attachment is used to measure the transmittance of a sample that diffuses light.

Sample size :

Min 30 mm (H) x 30 mm (W) x 0.5 mm (D)

Max 70 mm (H) x 80 mm (W) x 10 mm (D)

 

 

ARG-476/GPH-506 Polarizers

The light from a grating type spectrophotometer is always polarized. The ratio of the intensities of the S and P polarized light varies according to the wavelength and also differs from one grating to another for the same wavelength. The greater the angle of incidence of the beam on the sample, the greater the difference in the intensity of the S and P polarized reflected light, making measurements inaccurate if the absolute reflectance is measured at a high angle of incidence. In this case, a polarizer is required to accurately measure the absolute reflectance when the angle of incidence is 30° or greater.

Wavelength range:

250-750 nm(Model ARV-913)

250-2000 nm(Model ARN-914)

250-1600 nm(Model ARN-915i)

Rotation of plane of polarization:

0°(linearly polarized light in vertical
direction) to 90°(linearly polarized light
in horizontal direction)

Optional accessories continued

Wide incident angle sample holder (up to 85º)

6708-H163A for manual type

6708-H460A for automated type

PDU-755 Phase difference measurement unit (Polarizer with measurement software)