Wavelength Selection and Spectroscopy: The most basic function of a reflection grating is to decompose polychromatic light into monochromatic light. Its spectroscopic accuracy is determined by the grating density (line pairs/mm) and the grating material.
Beam Deflection and Scanning: By rotating or translating the grating, the direction of diffracted light can be dynamically changed, achieving beam scanning. For example, in laser printing systems, reflection gratings vibrate at a frequency of thousands of times per second, projecting the laser beam to different positions to form characters or images; in astronomical telescopes, gratings combined with rotating mirrors can achieve star tracking observations.
Phase Modulation and Wavefront Correction: Advanced reflection gratings can spatially modulate the phase of light waves through non-uniform grating distributions, used for laser focusing, holographic imaging, or optical calculations. For example, in ultrafast laser systems, phase modulation gratings can compress femtosecond pulses to a single period (<5 fs), breaking through traditional optical limits.
Intensity Distribution Control: By designing the duty cycle of the grating grating lines, the intensity distribution of diffracted light can be controlled. For example, in the field of optical communication, an 8:2 duty cycle grating can couple 90% of the light intensity to zero-order diffraction, with the remaining 10% used for signal monitoring, thus achieving efficient optical power allocation.