What does LASER stand for?
Light Amplification of Stimulated Emission of Radiation
What is spontaneous emission?
When a photon is applied to an atom, electrons gain energy and move to a high energy orbital, then emit a photon when returning to the ground state
If the photon is in the visible light spectrum, this is known as fluorescence.
What is stimulated emission?
Energised electrons act as energy sources for neighbouring atoms, leading to the release of 2 identical photons that are in phase with each other
What does population inversion refer to?
A sufficient number of atoms are energised, resulting in a majority of atoms with electrons in a higher energy state
What are the 3 properties of LASER light?
- Monochromatic: One specific wavelength
- Coherent: All waves are in phase
- Collimated: Highly directional
Describe how a LASER works.
A lasing medium is pumped with energy to allow stimulated emission, with mirrors reflecting photons until population inversion occurs, and light energy leaks through a small opening to create a laser beam
What are the clinical applications of infrared lasers?
- CO2 LASER: 10,600nm, absorbed by tissue water for bloodless cutting
- Nd:YAG LASER: 1064nm, penetrates 3-5mm depth, used in dermatology
What are visible light lasers used for?
Argon LASER: 488-515nm blue-green, penetrates to 2mm, used for blood coagulation while avoiding transparent tissues
What are the different classes of energy in Lasers?
- Class 1: Cannot emit radiation at any known hazard levels
- Class 2: Low-power visible lasers, <1 mW
- Class 3: Intermediate power, hazardous if directly viewed
- Class 4: High power, >500 mW, very hazardous
What is Q switching?
A technique used to pulse lasers to allow heat dissipation and reduce destruction to neighbouring tissues
What safety mechanisms are needed when using class 4 lasers?
- Appropriate training
- Specific safety goggles
- Environmental safety measures
When is there a particular risk with flammability and the use of Lasers?
During airway surgery, especially with high FiO2 or use of N2O
How can the risk of flammability during airway surgery be mitigated?
- Use of modern volatile agents that are non-flammable
- Reduced O2 concentration around the beam
What is the significance of reflected Lasers?
They are almost as powerful as the incident beam, necessitating the use of non-reflective instruments
