When we talk about spectroscopy, we generally refer to "atomic emission spectroscopy," where the wavelengths of elements in photoelectric spectroscopy are the atomic and ionic spectra of the elements. A spectroscope is a scientific instrument that decomposes light with complex composition into spectral lines. A spectrometer is also known as a spectrophotometer.
When a complex beam of light enters the incident slit of the spectrometer, it is first collimated by an optical collimator into a parallel beam, which is then dispersed into monochromatic light arranged by wavelength (color) as it passes through a diffraction grating. Different wavelengths of light leave the grating at different angles and are imaged in the projection slit by a focused reflector. Then a photoelectric conversion device is used to receive the light at different wavelengths, thus testing the optical power at different wavelengths. As we mentioned earlier, the integrating sphere system is a system in which the light from the lamp to be measured is scattered and homogenized and then transmitted to the spectrometer via optical fiber for spectroscopic testing.
A spectrometer typically includes an incident slit, collimator, dispersion element (grating or prism), focusing optics, and detector, while a monochromator usually also includes an outgoing slit, which allows only a very narrow band of light from the entire beam to illuminate a single element detector. Incident and emitted slits in a monochromator are often fixed in position and adjustable in width, and rotating gratings can scan the entire spectrum.
The development of optical detectors and fiber optic technology has led to the creation of fiber optic spectrometers to provide better solutions for optical testing of LEDs. In the 1990s, the rapid development of multi-element optical detectors in the microelectronics field, such as CCD arrays, photodiode (PD) arrays, etc., made it possible to produce low-cost scanners and CCD cameras. CCD and photodiode array (PDA) detectors allow fast scanning of the entire spectrum without moving the grating.
At present, the precision, accuracy, and sensitivity of the spectroscopic analysis can be comparable to chemical analysis; due to the continuous improvement of the spectroscopic analysis technology of carbon, sulfur, nitrogen, oxygen, and other elements, the spectrometer has become the most effective and economical solution for online component control in metallurgical industry and machinery manufacturing industry.