Tech mahindra overview and sample technical interview questions

Dear friends,

Today we will tell you about a company from the famous Mahindra group of India. The information and sample technical interview questions may be helpful to you in the interview. Let us start:

name: Tech Mahindra Limited

tagline: create the next wave

Founded in : 1986

Services: Tech mahindra provides services in IT, networking, IMS, BPO, BPM, product engineering, testing and other major IT services also.

Address:

Wing 1, Oberoi Estate Gardens, Chandivali, Andheri (E),
Mumbai 400 072,
Maharashtra, India.
Tel : +91 22 6688 2000
Fax: +91 22 2847 8959

website: www.techmahindra.com

Sample technical interview questions: Continue reading “Tech mahindra overview and sample technical interview questions”

How pumping is done in ruby laser

Pumping source: A helical flash lamp filled with xenon is used as a pumping source. The ruby crystal is placed inside a xenon flash lamp. Thus, optical pumping is used to achieve population inversion in ruby laser.

Ruby is a three level laser system. Suppose there are three levels E1, E2 and (E3 & E4). E1 is the ground level, E2 is the metastable level, E3 and E4 are the bands. E3 & E4 are considered as only one level because they are very closed to each other.

The ruby crystal is placed inside a xenon flash lamp and the flash lamp is connected to a capacitor which discharges a few thousand joules of energy in a few milliseconds. A part of this energy is absorbed by chromium ions in the ground  state. Thus optical pumping raises the chromium ions to energy levels inside the bands E3 and E4. This process is called stimulated absorption. The transition to bands E3 and E4 are caused by absorption of radiations corresponding to wavelengths approximately 6600 angstroms and 4000 angstroms respectively. The levels inside the bands E3 and E4 are also known as pumping levels.

Reference: This article is referred from my authored book “optics and lasers” having ISBN 81-272-2948-2. In case of any doubt, post in the comment section.

Active medium, active centers, puming source and optical resonator system in ruby laser

Active medium or active center: Chromium ions act as active centers in ruby crystal. So it is the chromium ions that produce the laser.

Pumping source: A helical flash lamp filled with xenon is used as a pumping source. The ruby crystal is placed inside a xenon flash lamp. Thus, optical pumping is used to achieve population inversion in ruby laser.

Optical resonator system: The ends of ruby crystal are polished, grounded and made flat. The one of the ends is completely silvered while the other one is partially silvered to get the output. Thus the two polished ends act as optical resonator system.

Reference: This article is referred from my authored book “optics and lasers” having ISBN 81-272-2948-2. In case of any doubt, post in the comment section.

Active medium or active center: Chromium ions act as active centers in ruby crystal. So it is the chromium ions that produce the laser.

Pumping source: A helical flash lamp filled with xenon is used as a pumping source. The ruby crystal is placed inside a xenon flash lamp. Thus, optical pumping is used to achieve population inversion in ruby laser.

Optical resonator system: The ends of ruby crystal are polished, grounded and made flat. The one of the ends is c

Active medium or active center: Chromium ions act as active centers in ruby crystal. So it is the chromium ions that produce the laser.

Pumping source: A helical flash lamp filled with xenon is used as a pumping source. The ruby crystal is placed inside a xenon flash lamp. Thus, optical pumping is used to achieve population inversion in ruby laser.

Optical resonator system: The ends of ruby crystal are polished, grounded and made flat. The one of the ends is completely silvered while the other one is partially silvered to get the output. Thus the two polished ends act as optical resonator system.

Note: I will explain the working in next article. Meanwhile, try to make the construction diagram yourself. In case of problem, contact me.

Reference: This article is referred from my authored book “optics and lasers” having ISBN 81-272-2948-2. In case of any doubt, post in the comment section.

ompletely silvered while the other one is partially silvered to get the output. Thus the two polished ends act as optical resonator system.

Note: I will explain the working in next article. Meanwhile, try to make the construction diagram yourself. In case of problem, contact me.

Reference: This article is referred from my authored book “optics and lasers” having ISBN 81-272-2948-2. In case of any doubt, post in the comment section.

Working of Ruby laser

In the last article, I have discussed construction of ruby laser. In this article, I will discuss working of ruby laser.

Ruby is a three level laser system. Suppose there are three levels E1, E2 and (E3 & E4). E1 is the ground level, E2 is the metastable level, E3 and E4 are the bands. E3 & E4 are considered as only one level because they are very closed to each other.

Pumping: The ruby crystal is placed inside a xenon flash lamp and the flash lamp is connected to a capacitor which discharges a few thousand joules of energy in a few milliseconds. A part of this energy is absorbed by chromium ions in the ground  state. Continue reading “Working of Ruby laser”