Cold Atom Physics and Laser Cooling Technology

According to the depth of human understanding of the micro world, contemporary physics has three main research fields, namely particle physics, atomic molecular and Optical Physics (AMO) and condensed matter physics. The field of atom and molecule and optical physics is between the other two. It does not rely on large-scale experimental equipment to carry out basic exploration work like particle physics, nor does it focus more research direction on the application that can be met like condensed matter physics. Therefore, in the field of atomic, molecular and optical physics, the practical significance of many research directions is not well known, such as laser cooling technology and cold atomic physics. The ultra-low temperature atoms obtained by laser cooling technology will play a key role in the development of human civilization in the foreseeable future because of the advantages that other states of matter (normal temperature atoms) do not have.

Observable Coherent Material Wave Length

Particles in the micro world have wave particle duality. The wavelength of De Broglie wave is λ = h / mv, which is inversely proportional to the momentum of particles. Because the average velocity of the room temperature atom reaches several hundred meters, its de Broglie wavelength is very small, about 1E-12 meters. Most of the atoms are in different quantum states, and the coherent length is very short, so it is difficult to form interference. The lowest temperature of cold atoms can reach several hundreds nK, the average speed can reach several centimeters per second, the wavelength of De Broglie is about 1E-7 meters, the coherent length is very long, and the coherent phenomenon can be observed macroscopically. When alkali metal atoms are cooled to the lowest energy state to produce Bose Einstein condensation, these lowest energy atoms will produce matter wave interference, which is the first time for human to observe the matter wave interference phenomenon of matter particles.

Atomic Interferometer

At present, the interference between two laser beams is widely used in interferometry. Because photons are not affected by gravity, it is difficult to measure gravity accurately by laser. The atom is obviously affected by gravity, so the atomic interferometer can effectively measure small changes in gravity and gravitational waves, etc., which will be the essential equipment in the future aerospace technology.

Precise Energy Level Structure

The collision between atoms is the main factor for the broadening of atomic energy level. Because the velocity of cold atom is very small and the temperature is very low, the collision between atoms is far less than that of hot atom, so the energy level width is far less than that of hot atom, which has a more accurate atomic energy level structure and a narrower transition spectrum, which is of great significance for the accurate measurement of atomic energy level and various constants.

Cold Atomic Clock

The accuracy of atomic clock depends on the accuracy of atomic energy level. At present, the atomic clock mainly uses the atomic fine level transition as the frequency standard. Because the energy level accuracy of cold atom is far better than that of hot atom, the cold atom clock will output more accurate frequency, so it will greatly improve the time accuracy of human beings and revolutionize the time and distance standards of human beings. It is the core technology of global positioning system and space positioning system in the future.

Control and Capture of Single Atom

It has long been a dream for human beings to manipulate atoms and molecules at the micro scale and change the arrangement and combination of atoms and molecules according to human's wishes. In surface physics, which is at the forefront of condensed matter physics, the position of some atoms can be moved and controlled by means of STM technology, but the capture of atoms and molecules can not be completed without the sample surface. Laser cooling technology just makes up for this defect.

Quantum State Manipulation

Cold atoms have more definite quantum states than hot atoms because of their slow motion and stable energy structure.

CoSF-D & CoSF-R High Power Single Frequency Fiber Laser

Connet 1.0um, 1.5um, 0.75um and 0.5um band kHz linewidth CW fiber laser is based on the main oscillator power amplification (MOPA) scheme. The seed laser uses a narrow linewidth and low noise single frequency fiber laser, such as CoSF-D or CoSF-R, whose linewidth is narrow to the order of kHz even less than 1kHz. Cascaded multi-stage low-noise fiber amplifier is used to increase the output power, the highest output power can reach 100W at 1064nm. Connet uses special relative intensity noise (RIN) suppression technology for realizing very low intensity noise for these high power single frequency fiber lasers.

These high power low noise kHz narrow linwidth single frequency fiber lasers are ideal laser for laser cooling, scientific research and other high end applications.