Introduction to Lasers

  • Lasers are devices that project light in a concentrated beam. The acronym stands for Light Amplification by Stimulated Emission of Radiation.
  • The unique characteristic of laser light is its coherence. This means that light waves are organised in a similar direction, wavelength and phase.
  • A basic laser consists of a gain medium – the material that produces the light, a cavity – to give the light a back and forth path, and an excitation mechanism – to provide energy to the system.

Functioning of Lasers

  • In electronics, a laser works by pumping energy into the gain medium to achieve population inversion. This is a state where more atoms are in high energy states than in low energy states.
  • Once population inversion is achieved, a photon travelling through the gain medium can stimulate an atom or molecule in an excited state to drop to a lower energy state, emitting a second photon.
  • This process causes a chain reaction or avalanche, leading to the emission of coherent light.

Application of Lasers in Medical Science

  • Lasers are used in various aspects of medicine, from diagnostic procedures to surgeries.
  • In ophthalmology, lasers are employed for vision correction in procedures like LASIK and for treating certain retinal disorders.
  • In dermatology, lasers are used for skin resurfacing, tattoo removal and treatment of vascular abnormalities.
  • Lasers are also a key tool in oncology with applications in cancer diagnosis and in therapies like photodynamic therapy.
  • They can be used in dentistry for procedures such as tooth whitening and in surgical gum treatments.

Advantages and Limitations of Medical Lasers

  • Advantages: Lasers offer precision and control which prevent damage to surrounding tissues. They can target difficult-to-reach areas and can be minimally invasive, reducing discomfort and recovery time.
  • Limitations: The technology requires specialised training and can be expensive. Not all types of tissues respond well to laser therapy and there are potential risks of thermal damage.

Accurate comprehension of how lasers work is crucial to understand their applications and implications in medical sciences, an important part of Medical Physics.