LASER (Light Amplification by Stimulated Emission of Radiation) is an optical source that emits photons in a coherent beam. Laser light is typically near-monochromatic, i.e., consisting of a single wavelength or colour, and emitted in a narrow beam.
A laser is a device that emits light (electromagnetic radiation) through a process of optical amplification based on the stimulated emission of photons. Many materials have been found to have the required characteristics to form the laser gain medium needed to power a laser, and these have led to the invention of many types of lasers with different characteristics suitable for different applications.
The laser was proposed as a variation of the maser principle in the late 1950s, and the first laser was demonstrated in 1960. Since that time, laser manufacture has become a multi-billion dollar industry, and the laser has found applications in many fields including science, defense/aerospace, medicine, and consumer electronics.
Scientists have for the first time created laser light using living biological material: a single human cell and some jellyfish protein. Scientists have for the first time created laser light using living biological material -a single human cell and some jellyfish protein. Seok- Hyun Yun, an optical physicist at Harvard Medical School and Massachusetts General Hospital in Boston created the living laser with his colleague Malte Gather. This was the first time that biological materials were used to build a laser and generate light from something living.
Building a laser requires two things: a lasing material that amplifies light from an external source (a ‘gain medium’) and an arrangement of mirrors (an ‘optical cavity’), which concentrates and aligns the light waves into a tight beam. Until now, the gain medium has only been made from non-biological substances such as doped crystals, semiconductors or gases, but in this case the researchers used enhanced green fluorescent protein (GFP) – the substance that makes jellyfish bioluminescent, which is used extensively in cell biology to label cells.
The team engineered human embryonic kidney cells to produce GFP, and then placed a single cell between two mirrors to make an optical cavity just 20 micrometers across. When they fed the cell pulses of blue light, it emitted a directional laser beam visible with the naked eye – and the cell was not harmed. The width of the laser beam is tiny and fairly weak in its brightness compared to traditional lasers, but an order of magnitude brighter than natural jellyfish fluorescence, with a beautiful green colour.
Back in 2008, scientists Martin Chalfie, Roger Tsien, and Osamu Shimomura received the Nobel Prize in chemistry for their roles in bringing Green Fluorescent Protein (also known as GFP, the protein responsible for luminosity in the jellyfish A. Victoria) and its diverse applications to the front lines of scientific research.
The team suggested that biologists could turn cells of interest into lasers to study them. The light produced has a unique emission spectrum related to both the structure of the cell and the proteins inside it. The researchers also suggest possible medical applications. Doctors today shine lasers into the body to gather images or to treat disease by attacking cells. The researchers think that lasers could instead be generated or amplified inside the body, where they could penetrate the relevant tissues more deeply.
But more work is needed first – including developing the laser so that it works inside an actual living organism. To achieve this, researcher envisages integrating a nano-scale optical cavity into the laser cell itself. Technologies to make such cavities are emerging and once they are available they could be used to create a cell that could self laser from inside tissue. External light is needed to stimulate the laser action, which would be difficult in the body, potentially limiting the technique to thin-tissue systems or cells in culture or suspension.
Use of technology
i. Biologists could turn cells of interest into lasers to study them.
ii. The light produced has a unique emission spectrum related to both the structure of the cell and the proteins inside it.
iii. By analysing the pattern one can get some idea of what is happening inside the cell.
iv. Doctors shine lasers into the body to gather images or to treat disease by attacking cells. Lasers could instead be generated or amplified inside the body, where they could penetrate the relevant tissues more deeply.