Applications of laser, optics & photonics are abundant. They include in our everyday life to the most advanced science, e.g. information processing , light detection, spectroscopy,  Laser cooling telecommunications, lighting , information processing, lighting, metrology, laser material processing , spectroscopy, medicine, military technology, bio photonics, agriculture, robotics, and visual art.  They are also used in Spectroscopy, Heat Treatment, Lunar laser ranging, Photochemistry, Laser scanner, Nuclear fusion, Microscopy, Modelling and Designing of optical systems using physical optics, Superposition and interference, Diffraction and optical resolution and many more.
The laser has driven both scientific and technological innovation in every facet of modern life. The laser shows the sign of continuing its unique and creative role. The role of the laser is expanding. The main reason why the laser is so special because it allows us to harness light in unique way. Finding new uses for laser technology will provide the most dramatic breakthroughs. Some of the development will be far-reaching medical diagnosis, dramatically more efficient computers and communications, laser boost energy application and security and protection.

Biomedical optics is a field that studies the basic principles of interaction between light and biological tissues, cells and molecules and develop new technologies for use in basic research and clinical applications. Biomedical optics is interdisciplinary since it covers all aspects of optical imaging and spectroscopy from subcellular length scales to large tissue volumes and attract researchers and users of optical physics, biophysics, biochemistry, engineering, biology, medicine, mathematics and computer science. This research encompasses all aspects of optical imaging and spectroscopy ranging from subcellular length scales to large tissue volumes such as the brain and breast. It is concerned with cancer detection & therapeutics, non-invasive tissue biopsy, functional activation & mechanisms, and the coupling between physiological responses and optical signals. In medicine it focuses on tissue and blood to detect, diagnose and treat diseases non-invasively.

Lasers are devices that produce light with properties very different than those of other light sources, e.g., incandescent bulbs or LEDs. These unique characteristics enable a remarkably wide range of applications. Laser light can travel large distances as a narrow beam without diverging, allowing it to be used in laser pointers, laser light shows, and even for communication between satellites. Whereas, the high-intensity lasers can be used for a variety of micromachining applications, including cutting/marking materials such a ceramics, glass, and metals as well as safe ablation of human tissue. 

Photochemistry is the branch of chemistry concerned with the chemical effects of light. In nature, photochemistry is of immense importance as it is the basis of photosynthesis, vision, and the formation of vitamin D with sunlight. It is also responsible for the appearance of DNA mutations leading to skin cancers. One of the fundamental principles of photochemistry is that the energy of light is absorbed by matter, and this energy can be used to drive chemical reactions.

Applications of photochemistry in everyday life include decontamination of drinking water, production of hydrogen fuel, and food processing. Another application is the production of light under physiological conditions through photosynthesis with plants or artificial systems based on semiconductor nanomaterials such as quantum dots (QDs) which have unique optical properties compared to organic dyes due to their size-tunable spectrum. In particular, photochemical studies have been used extensively for research on new drug development as well as solar energy conversion technology.

Optics is becoming integrated in defense systems other than optical systems, such as into microwave radars, using radio-frequency (RF) photonics. Modern defense systems are migrating toward optically based imaging, remote sensing, communications, and weapons. Specialty optics play a role in several areas for troops on the ground from night vision goggles, helmet recording camera systems, and sighting equipment such as thermal imaging sights, and spotting scopes.

 There have been significant advances in optics and photonics for defense system. Some of the key areas include surveillance, night vision, laser systems, fiber-optics systems, chemical and biological detection, and optical processing.

Photonics makes laser-guided weapons more accurate, provides lasers for critical missile defense capabilities and permits personalized use of flexible display technology, which allows our men and women in uniform to remain informed and safe during operations with night vision, GPS and physiological feedback.

Laser, a device that stimulates atoms or molecules to emit light at particular wavelengths and amplifies that light, typically producing a very narrow beam of radiation. The emission generally covers an extremely limited range of visible, infrared, or ultraviolet wavelengths. Many different types of lasers have been developed, with highly varied characteristics.

Lasers deliver coherent, monochromatic, well-controlled, and precisely directed light beams. Most laser applications fall into one of a few broad categories: (1) transmission and processing of information, (2) precise delivery of energy, and (3) alignment, measurement, and imaging.

Lasers are used in optical disc drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic, and free-space optical communication, semiconducting chip manufacturing (photolithography), laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and in laser lighting displays for entertainment.

A quantum sensor is a gadget that adventures quantum relationships, for example, quantum entrapment to accomplish affectability or the determination that is superior to can achieve utilizing just traditional frameworks. A quantum sensor can quantify the impact of the quantum condition of elective framework independent from anyone else. Quantum sensor is the term utilized as a part of different settings wherever caught quantum frameworks are intimidated to improve more touchy magnetometers or nuclear timekeepers. Quantum Photonics is to investigate the crucial highlights of quantum mechanics and furthermore the work towards future photonic quantum innovations by controlling, producing and estimating single photons and in addition the quantum frameworks that emanate photons.

A photovoltaic system is a special electrical system that produces energy from a renewable and inexhaustible source: the sun.

A photovoltaic (PV) panel, commonly called a solar panel, contains PV cells that absorb the sun’s light and convert solar energy into electricity. These cells, made of a semiconductor that transmits energy (such as silicon), are strung together to create a module. When the semiconductor is exposed to light, it absorbs the light's energy and transfers it to negatively charged particles in the material called electrons. This extra energy allows the electrons to flow through the material as an electrical current. Unlike traditional energy sources, when PV solar panels create electricity, they don't emit harmful greenhouse gases, pollute groundwater or deplete any natural resources. In addition, you help protect the planet by cutting back on your dependence on nonrenewable energy

Significant investigation in optics material science is additionally quick to quantum optics and rationality. In optics material science, look into is additionally animated in territories, for example, ultra-short electromagnetic fields, the nonlinear reaction of disengaged iotas to an extreme, quantum properties of the electromagnetic field, and the molecule pit connection at high fields. Optomechanics  refer to the sub-field of physics involving the study of the interaction of electromagnetic radiation (photons) with mechanical systems via radiation pressure (also see cavity optomechanics) or the manufacture and maintenance of optical parts and devices.

Optics passage and genuine infiltration can vary completely depending upon the absorptivity of the astrophysical atmosphere. Optics infiltration is a measure of the obliteration coefficient or absorptivity up to positive 'significance' of a star's beautifiers. The doubt here is that either the ending coefficient or the area number thickness is known. These can generally be figured from various conditions if a significant part of the information is pondered the substance makeup of the star. Optics profundity can henceforth be thought of as the imperiousness of a medium. The end coefficient can be discovered using the trade condition.

Bio photonics can also be described as the advance and examined, i.e. scattering material, on a microscopic or macroscopic scale application of optical techniques particularly imaging, to study of biological molecules, tissue and cells. One of the main benefits of using optical techniques which make up bio photonics is that they reserve the reliability of the biological cells being.

Optoelectronics is the field of technology that associates the physics of light with electricity. It incorporates the design, study and manufacture of hardware devices that convert electrical signals into photon signals and photons signals to electrical signals. Any device that operates as an electrical-to-optical or optical-to-electrical is considered an optoelectronic device. Optoelectronics is built up on the quantum mechanical effects of light on electronic materials, sometimes in the presence of electric fields, especially semiconductors. Optoelectronic technologies comprise of laser systems, remote sensing systems, fibre optic communications, optical information systems, and electric eyes medical diagnostic systems.

Nanoparticles and nanomaterial have different fundamental properties. The applications of laser radiation in the nanotechnology are ranging from fabrication, melting and evaporating. This process is done to change the shape, structure, size and size distribution. The progress in the field of nanotechnology is greatly relied on the uses of lasers. The combination of laser and nanotechnology in the field of cancer treatment has made a good progress over the year. There are many application of laser in the nanotechnology which will be discussed in detail in this section.

Two-photon microscopy, also referred to as two-photon laser scanning microscopy, is a further refinement of precision fluorescence microscopy. It is an alternative to confocal and deconvolution microscopy that provides distinct advantages for three-dimensional imaging. In two-photon microscopy, two photons of light with double the wavelength are used to excite the same or similar fluorescent dyes. However, only one photon is released when the electron drops down to its more stable orbital. This will have the same wavelength as the equivalent one-photon fluorescence method (i.e., slightly longer than half the excitation wavelength). The principal advantages of two-photon microscopy are reduced phototoxicity, increased imaging depth, and the ability to initiate highly localized photochemistry in thick samples. 

Plasma physics is the self-consistent description of charged particles and electromagnetic fields. Gravitational Waves Generated by Laser-Matter Interactions The research is performed in the area of gravitational waves generation which connects fundamental gravitational theory with the laser—plasma interaction.

Laser-produced plasmas are plasmas produced by firing high-intensity beams of light. Laser-produced plasmas have been used to create short bursts of x-rays and to accelerate particles — so-called plasma-based accelerators. Laser produced plasmas are also useful for recreating astrophysical plasmas in the laboratory. Plasma is used in television, neon signs and fluorescent lights. Stars, lightning, the Aurora, and some flames consist of plasma.

Nanophotonics or nano-optics is the study of the behavior of light on the nanometer scale, and of the interaction of nanometer-scale objects with light. It is a branch of optics, optical engineering, electrical engineering, and nanotechnology. It often (but not exclusively) involves metallic components, which can transport and focus light via surface plasmon polaritons. Metamaterials are artificial materials engineered to have properties that may not be found in nature. They are created by fabricating an array of structures much smaller than a wavelength. The small (nano) size of the structures is important: That way, light interacts with them as if they made up a uniform, continuous medium, rather than scattering off the individual structures.

Laser spectroscopy is a versatile diagnostic tool for analytical applications and recent advances in semiconductor laser technology (QCL, DFB, VCSEL) combined with selective and sensitive spectroscopic detection techniques have led to the development of new diagnostic tools for trace gas and isotope analysis.
Raman spectroscopy and microscopy techniques are employed for the analysis of rotational, vibrational, and other low-frequency modes in a molecular system. The interaction of the laser light with the system causes shifting up or down of the energy of the laser photons. This shift in energy provides data about the molecular bonds and thereby the molecule itself. In this way, the molecule being tested can be identified.
The lasers commonly employed in optical microscopy are high-intensity monochromatic light sources, which are useful as tools for a variety of techniques including optical trapping, lifetime imaging studies, photobleaching recovery, and total internal reflection fluorescence. In addition, lasers are also the most common light source for scanning confocal fluorescence microscopy, and have been utilized, although less frequently, in conventional widefield fluorescence investigations.

Nonlinear optics (NLO) is the branch of optics that describes the behavior    of light in nonlinear media, that is, media in which the dielectric polarization P responds nonlinearly to the electric field E of the light. The nonlinearity is typically observed only at very high light intensities (values of atomic electric fields, typically 108 V/m) such as those provided by lasers. Above the Schwinger limit, the vacuum itself is expected to become nonlinear. In nonlinear optics, the superposition principle no longer holds.

Terahertz optics is a branch of optics and photonics that studies electromagnetic radiation with a wavelength between 0.1 and 1 millimetre, so-called because this corresponds to a frequency of approximately one terahertz (a trillion hertz). Topics covered include terahertz sources, on- and off-resonant control using intense terahertz pulses, quantum cascade lasers, superconducting terahertz emitters and terahertz plasmonics. Terahertz electromagnetic radiation is one of the last remaining unexplored regions of the electromagnetic spectrum; occupying a large portion of the spectrum between the infrared and microwave bands. Photonic devices are components for creating, manipulating or detecting light. This can include laser diodes, light-emitting diodes, solar and photovoltaic cells, displays and optical amplifiers.

The clinical practice of optometry for the pediatric patients is done to reduce the risk of vision loss and facilitate normal visual development. This pediatric population can be applied to patients between birth and 18 years of age.