Optical spectrometer Spectrometry diffraction grating VHP grating Prism PGP spherical Conical surface Cone LENs Monochromator

 diffraction grating VHP grating Prism PGP spherical

The Optics of Spectrometry: A Guide to Spectroscopy Gratings

Direct-vision, dispersing prism-grating-prism (PGP) spectrograph used... | Download Scientific Diagram 

https://www.avantes.com/support/theoretical-background/introduction-to-spectrometers/

https://support.zemax.com/hc/zh-cn/articles/1500005578762-How-to-build-a-spectrometer-theory

Conical surface Cone 

Optical  Conical surface Cone grating Conical surface Cone  IR filter  Grating Equation

Optimization and Performance Evaluation of Apodization Function for Fiber Bragg Grating as Vital Sign Sensor | SpringerLink

Optical  Cone grating filter Optical filtering