- August 2018-Nov 2018, Open-Ended Lab at NISER
- Guide: Dr. Ritwick Das, NISER (currently at IIT Delhi)
Light amplification by stimulated emission of radiation, acronymed LASER, finds itself not only in a wide range of applications but is also of much theoretical and experimental interest. In this experiment, the
properties of a particular laser system, viz. Helium-Neon laser was analyzed. After careful analysis, a suitable configuration was chosen to obtain a beam of sufficient intensity and suitable radius so as to illuminate a miniature spring for solving its structure. In the first part of the experiment, the wavelength of the Helium-Neon laser was determined to be λ = 619.31 ± 14.58. The analysis of different
resonator configurations was undertaken to study the beam shape and power output of the beam. The quality of the beam was analyzed, M2 was found to be 0.751 ± 0.054. Having studied various laser parameters, HR flat/flat HR flat/1000mm resonator configuration was chosen with a resonator length of 450 mm, for laser interferometry in order to solve the structure of a spring. A left-handed spring was made manually, and it’s diameter(a) and pitch(p) were determined by using principles of interference and diffraction to be a = (9.63 ± 0.13) × 10−2 mm and p = 0.066 ± 0.002 cm. The pitch was also determined using a traveling microscope and was found to be p = 0.066 ± 0.007 cm, which is in excellent agreement.
Also, a brief discussion of further experimental work, which can be performed using apparatus, is presented.