11. In radio astronomy the air mass ( which influences the optical path length ) is not relevant. 12. This in turn shifts the band edge and changes the optical path length in the lasing cavity. 13. Today, acquisition is usually done using a CCD camera mounted in the optical path of the microscope. 14. The expression for the optical path length can also be written as a function of the optical momentum. 15. The gradient theorem can then be applied to the optical path length ( as given above ) resulting in 16. An additional photomultiplier system viewed a beam splitter in the optical path and was used as a star mapper. 17. The amount of light absorbed in each spectral line increases with the number of molecules along the optical path . 18. When a human or object moves into the optical path , the reflected beam bounces back from the object. 19. Where is the optical path length, is a molar absorbance at unit path length and is a concentration. 20. Consequently, the ability to define an optical path is 1000 times better when using beam profilers over irises.
