February-2018 Seminar

Title : Generation of biphoton orbital angular momentum eigenmodes with asymmetric optical vortex beam

Date : 21-02-2018
Time : 00:16:00
Speaker : Mr. Jabir M. V
SRF
Area : Atomic, Molecular and Optical Physics
Venue : Room No 113, PRL Thaltej

Abstract

Quantum entanglement, the quintessential curious phenomenon, shows strong non-classical correlations in joint two separate quantum systems, and plays a crucial role in many important applications in quantum information processing, including quantum communication, quantum cryptography and teleportation. Orbital angular momentum (OAM) entanglement in the biphoton eigenmodes has high potential in the field of quantum communication as it can give high dimensional entanglement between the photon pairs. We report a study of biphoton OAM eigenmodes generated in the spontaneous parametric down-conversion process using asymmetric vortex beam. With the help of spiral phase plate (SPP) we generate the symmetric optical vortex beam. The OAM content for different asymmetry is verified using OAM projective measurements. Using the tailored OAM pump beam we have studied the biphoton OAM eigenmodes in the SPDC process, and shown that one can tune or select the desired eigenmodes by simply controlling the asymmetry in the pump beam. Calculation of Schmidt number(K) of the total OAM Hilbert space spanned by the biphoton modes showed that proper tailoring of OAM in the pump beam will increase the dimensionality of the state.

Title : Glaciation on Mars: Recent findings

Date : 16-02-2018
Time : 14:00:00
Speaker : Mr. Rishitosh K. Sinha
Scientist/Engineer 'SD'
Area : Planetary Sciences Division
Venue : Room 113, Thaltej Campus

Title : The Lunar Magma Ocean (LMO) - Myth or Misconception?

Date : 09-02-2018
Time : 16:00:00
Speaker : Dr. Dwijesh Ray
Scientist 'SE'
Area : Planetary Sciences Division
Venue : Room 113, Thaltej Campus

Title : Astrochemistry 2017 - Where we stand?

Date : 09-02-2018
Time : 00:17:00
Speaker : Dr. B Sivaraman
Area : Atomic, Molecular and Optical Physics
Venue : Room No 006, PRL Thaltej

Date : 08-02-2018
Time : 16:00:00
Speaker : Dr. Main Pal
Post doctoral fellow
Area : Astronomy & Astrophysics Division
Venue : Seminar Room # 113/114 (Thaltej Campus)

Abstract

Understanding the nature of the unresolved central engine has reached to a great level in Seyfert 1 galaxies. Though we do not understand actual character of the central engine, we study these sources through timing as well as spectroscopic tools. Using these tools, we investigate them in the multi-wavelength range such as the UV/Optical as well as the X-ray bands. One of the major interest is to understand the UV/Optical emission variability and its connection to the X-ray emission. In this direction, I will be discussing about the recent results on a narrow line Seyfert 1 galaxy NGC 4593 and a broad line Seyfert 1 galaxy 1H 0419-577. In the NGC 4593, I have made a detailed study on strongly correlated UV/Optical/X-ray emission and I found that the real disk may not be as the predicted one Shakura-Sunyaev standard disk. In the 1H 0419-577, the marginally correlated UV/Optical/X-ray emission show a complex origin of the UV/Optical variability possibly a mixture of reprocessing and the changes in the geometry of X-ray emitting corona. I will also present some ongoing work on a NLS1 Mrk 766. This shows moderate harder when brighter state and soft emission is leading to the hard emission.

Title : Generation of optical vortices in mid-IR with the help of optical parametric oscillators

Date : 05-02-2018
Time : 00:16:00
Speaker : Mr. Varun Sharma
Senior Research Fellow
Area : Atomic, Molecular and Optical Physics
Venue : Room No: 113, PRL Thaltej

Abstract

Optical parametric oscillators (OPO) have proved their versatility as a source of coherent radiation over a wide range of wavelengths, which is not possible to achieve with conventional Lasers. For example, the mid-IR wavelength range which is also known as fingerprinting region due to the presence of fundamental absorption bands of various molecules and widely used for high resolution molecular spectroscopy, can not be accessed without the use of nonlinear parametric processes and or OPOs. The OPO sources conventionally produce output radiation in Gaussian intensity distribution. However, generating mid-IR radiation in vortex spatial intensity profile, one can extend the advantages of such sources in terms both spectral and spatial parameters. Using a PPLN based OPO we have transferred optical vortices at near-IR wavelength directly to the mid-IR region and produced high power and higher order optical vortices continuously tunable across 2.3 μm to 3.3 μm. In this talk, I will discuss about the generation technique for optical vortices in mid-IR and their characteristics.

Title : XSM payload FPGA RTL code development process and its qualification

Date : 02-02-2018
Time : 16:00:00
Speaker : Mr. Arpit R. Patel
Scientist/Engineer-SD
Area : Planetary Sciences Division
Venue : Room 113, Thaltej Campus