Ms. Samaneh Birzhandi, Ms. Malihe Ranjbaran, Dr. Seyed Mohammad Hosein Khalkhali, Dr. Seyedeh Mehri Hamidi, Prof. Mohammad Mehdi Tehranchi,
Volume 7, Issue 2 (8-2013)
Abstract
Recently atomic magnetometers are one of the best tools in biomagnetic measurement such as magnetic field of brain and heart. In this paper, the technology of optically pumped atomic magnetometer based on circularly polarized light absorption pumping is described. We have been investigated a new method for measuring polarization effect in an alkali vapor based on polarized light transmission. In addition several magnetometers’ response factors such as cell temperature, laser’s intensity are introduced and reviewed. Our results show that the difference between absorption of circular and linear light not only depends on polarization, but also in number of polarized atoms.
Dr Maryam Sanaee, Prof Abbas Zarifkar,
Volume 11, Issue 1 (1-2017)
Abstract
The modulation response, relative intensity noise (RIN) and frequency noise (FN) characteristics of quantum dot (QD) lasers are investigated theoretically in the presence of an external optical beam. Using small signal analysis of the rate equations for carriers and photons, it is demonstrated that by injecting excess carriers into the QDs excited state through optical pumping, the modulation response of QD laser enhances and its bandwidth increases. The external optical pump also helps QD laser to turn on during shorter delay time. Further, it is deduced that the RIN level of QD laser reduces and the damping factor increases due to external beam. Moreover, the frequency noise level of QD laser and correspondingly its linewidth decreases by applying the optical beam.
