PHOTONICS

                               Lasers & Amplifiers Typically Used in Our Experiments  

Lasers and Amplifiers

  Solid-State Nonlinear Optical Crystals

 Photodetectors

 Electronics

       Data-Acquisition and Data-Analysis

Question: What is Laser Physics ? 

                 What is Nonlinear Optics (NLO) ?   

Answer: Study of light-matter interaction is called laser physics. Where matter is refereed to atom, molecule, or solid.  During this light-matter interaction when intensity in the light beam is large enough so that its electric field become comparable to the existing atomic field in the medium, the light-matter interaction become nonlinear i.e. polarization induced in the medium scales nonlinearly with the applied electric field. Branch of laser physics, which deals with light-matter interaction in the nonlinear regime, is called nonlinear optics. Nonlinear optical processes are characterized by frequency mixing and are generally practiced with high peak power pulsed lasers. Today, nonlinear optics is the most productive area within the entire field of laser physics ! 

Question: What is a Laser ?   

Answer:  Laser physics has led to development lasers, which is a quantum device that works on principle of stimulated emission. Lasers are  used for many-many practical applications. Examples of such applications are scientific & engineering research, industry, and medical science. For more detail about lasers and how it works click on the link below. 

                                             Click: Laser 

Question: What is Single Photonics ?   

Answer: Single Photon is a quantized mode of electromagnetic radiation. Energy of single photon at wavelength 500 nm  is equal to 1.42 X 10^-19 (10 raise to the power minus 19) Joule, which is approximately 2.5 eV.    

             Single Photonics is a new emerging field of photonics in which light-matter interaxtion is practiced with single photons. Single photons are likely to replace electrons from existing electrical, electronics, computing, and communication devices. 

Question: What is Quantum Information Science (QIS) ?   

Answer: Quantum information science (QIS), which is union of quantum mechanics and information science is very new and very fast-growing field of research. Major goal of quantum information science is to improve performance and security of information systems such as computers and internet. Laser physics provide a suitable platform to meet this goal. 

Question: What is Quantum Photonics ?

                 What role does quantum photonics play for Quantum Computation and Quantum Communication?

Answer: Quantum photonics, which  is the most recent application of laser physics, use quantum nature of photons such as superposition and entanglement among single photons to built next generation of quantum computers and quantum internet.  In this application single photons are used as quantum particles, and qubit is encoded in the state of polarization of the photon. Major advantages of photonic qubit are following: (1) photonic qubit is negligibly affected by decoherence, which is a major limitation for building quantum computer, (2) photonic qubit function at room temperature and therefore experiments using photonic qubit do not require cryogenic cooling, (3) experimental techniques for generation, manipulation, transmission, and detection of photons are already well developed. Based on above advantages photonic qubit provides very suitable platform for processing quantum information and building next generation of photonic quantum computer. Therefore, quantum photonics is playing vital role for very new and fast-growing field of quantum computation. Quantum photonics along with superconducting circuits are two most competing platforms for building next generation of practical quantum computers. A large-scale quantum computer based on quantum photonics is currently under development by company: PsiQuantum (Click: https://www.psiquantum.com/). More detail about photonic quantum computing can be found in a published paper: A Manufacturable Platform for Photonic Quantum Computing, Nature 641, page 876 (2025): Download: Photonic Quantum Computing Pdf. 

          Photonic qubit offers further advantages, which are following: (4) photonic qubit is the best and the fastest carrier of information, (5) photonic qubit is compatible with existing fiber telecommunication technology, and (6) entanglement among photonic qubits can be used to design quantum interconnections among remotely located nodes of a quantum network. Based on above advantages photonic qubit provides the only platform (with no second option) for building next generation of global scale quantum internet. Therefore, quantum photonics is playing pivotal role for very new and very rapidly advancing field of quantum communication.

Question: If you need to know anything about Laser Physics & Technology then where should you look for?

Answer:   Encyclopedia of Laser Physics and Technology (Wiley, 2008)

                                                   By Rudiger Paschotta, 

                     Click :  (www.rp-photonics.com/encyclopedia)              

Question: How to win a Nobel Prize ?

Answer:  Switch your research to Laser Physics. Recently, highest number of Nobel Prizes are being awarded to those researchers who work with Lasers.

         Physics Nobel Prizes Associated with Laser Physics 

   Nobel Prize for year 1964: For Quantum Electronics / Laser-Maser Principle

                                 C. H. Townes, N. G. Basov, and A. M. Prokhorov

                                                       Click: Nobel -Prize-1964 

  Nobel Prize for year 2018: For Method of Generating High-Intensity Ultra-Short Optical Pulses

                                                G. Mourou and D. Strickland

                                                         Click-  Nobel-Prize-2018

Nobel Prize for year 2023: For Experimental Methods that Generate Attosecond Pulses of Light for the

                                              Study of Electron Dynamics in Matter.  

                                               P. Agostini, F. Krausz, and A. L' Huillier

                                                     Click: Nobel-Prize-2023/ 

                        Nonlinear Optical Frequency Conversion

       M. M. Fejer, Physics Today p. 25,  May 1994.

               Download: (Frequency-Conversion) Pdf                 

                                                  Tunable Solid-State Laser

        Spectroscopic and Laser Characteristics of Ti:Al2O

       P. F. Moulton,  JOSA B 3 (1), 125 (1986).

                                                    Download: (Ti:Sapphire) Pdf

                   Chapter 9: Optical Parametric Oscillator                                                                 Robert L. Byer

                                 Quantum Electronics eds. H. Rabin and C. L. Tang  (1975)

                                                     Vol. 1 Part B Nonlinear Optic

                                             Download: (Review-OPO)    

                                             Solid-State Nonlinear Optical Crystals

Lithium Triborate (LBO),

Beta-Barium Borate (BBO),

Potassium Titanyl Phosphate (PPKTP),

Lithium Niobate(PPLN),

Potassium Titanyl Arsenate (PPKTA),

Lithium Tantalate (PPLT),

      Indium Gallium Phosphate (InGaP), 

       Photonic Crystal 

Photodetector

(For Detection of Entangled Photons)

 Single-Photon Detectors for Optical Quantum Information Applications

 R. H. Hadfield, Nature Photonics 3, 696 (2009)

Download: (Detector-QIS) Pdf

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