23.png - Red light of wavelength 640nm is incident normally on a diffraction grating having a line spacing of 1.7 x 10 6m, as shown in Fig. | Course Hero
High Powered 640m Single Mode Red Laser Diode, 640nm SM Laser Diode | Berlinlasers
Thorlabs - MPRP1D2 455 nm (12.5%) / 640 nm, 275 mW (Min) LED on Metal-Core PCB, 300 mA