Spectrometer-Based Reflectance Measurement Solutions

2025-12-12

01 Principle of Reflectance Measurement

Reflection phenomena can be categorized into two primary types: specular reflection and diffuse reflection. When light strikes an extremely smooth surface (such as a mirror or glass), specular reflection occurs, where the angle of reflection equals the angle of incidence. In contrast, when light encounters a rough or matte surface, diffuse reflection takes place, scattering light in various directions. In everyday life, most object surfaces exhibit a combination of both reflection types. Optosky's measurement software calculates reflectance using a standard formula based on background and reference spectra:

S_λ= Intensity of the sample spectrum at wavelength λ

D_λ= Intensity of the background spectrum at wavelength λ

R_λ= Intensity of the reference spectrum at wavelength λ

Background Spectrum: The spectrum measured by the spectrometer with no active light source.

Reference Spectrum: The spectrum obtained from a calibrated diffuse reflectance standard (white reference).

02 Typical System Configuration

A typical system for measuring reflectance includes the following components:

PC with spectrometer control software
Spectrometer
Light Source
Optical Fibers
Reflectance Integrating Sphere
Diffuse Reflectance Standard (White Board)

Table 1: Reflectance Measurement System Configuration

	UV-Vis Range	NIR Range
Spectrometer	ATP2000P	ATP8000
Light Source	ATG1020H	ATG1020H
Reflectance Integrating Sphere	ATST150R or ATST150	ATST150R or ATST150
Diffuse Reflectance Whiteboard	Reflectance Whiteboard	Reflectance Whiteboard
Optical Fiber	UV Fiber *2	IR Fiber *2
Attenuator	(Optional, requires an additional fiber)

*You can see all the products in this website: www.optosky.net

ATG1020H Light Source Overview

Optosky's ATG1020H Deuterium-Halogen Combination Light Source employs a high-stability Hamamatsu deuterium lamp bulb for consistent output from 180-400 nm. Its halogen component utilizes a long-life, highly stable Osram bulb with a lifespan of up to 5,000 hours, paired with a custom-designed, reliable constant-current driver. The ATG1020H is characterized by its long operational life, minimal intensity decay, and high output power, making it suitable for both benchtop and portable micro-spectrometer applications. An optional cuvette holder accessory allows the ATG1020H to be used directly for transmission and absorption testing of liquid samples or filters.

Basic Operational Steps for the Light Source

Connect the 12V power adapter to the source and turn on the main power switch.
Start the light source and allow a 10-minute warm-up period to achieve stable output.
Once optical fibers are connected, the deuterium and halogen lamps can be activated independently via their respective switches.

03 Hardware Operation for Reflectance Measurement

To set up and perform a reflectance measurement, follow these steps:

Connect the light source to the integrating sphere's input port, and connect the sphere's output port to the spectrometer using optical fibers.
Connect the spectrometer to a PC via USB and launch the control software.
Power on the light source using its 12V adapter.
With the light source OFF, collect a Dark Signal spectrum (no light input to the spectrometer).
Turn the light source ON, allow it to warm up for 10 minutes, place the Diffuse Reflectance Standard White Board at the sample port of the integrating sphere, and collect the Reference Signal spectrum.
Replace the white board with your Sample at the sample port and measure its reflectance spectrum.