 # LASIK eye surgery uses pulses of laser light to shave off tissue from the cornea, reshaping it. A typical LASIK laser emits a 1.0-mm-diameter laser beam with a wavelength of 193 nm. Each laser pulse lasts 15 ns and contains 1.0 mJ of light energy. – How powerful is a single laser pulse?

– What’s the strength of a light wave during the incredibly brief pulse?

The main objective of this question is to find how powerful is a single laser pulse and strength of a light wave.

This question uses the concept of peak power. Peak power is the term used to describe the highest optical power that a laser pulse may produce. It is a measure of the energy content of a laser pulse relative to its temporal time, or pulse width, in more general terms.

a) First we have to calculate the how powerful is a single laser pulse. The amount of energy released in relation to the amount of time it was released will determine the power. So:

$\space P \space = \space \frac{E}{t}$

By putting the values, we get:

$\space = \space \frac{1 \space . \space 10^-3} {1.5 \space . \space 10 ^-8}$

$\space = \space \frac{0.66 \space . \space 10^-3}{10^-8}$

$\space = \space 0.66 \space . \space 10^5$

$\space = \space 66666.66$

$\space = \space 66.7 \space kW$

b) Now we have to find the strength of light wave.

So:

$\space I \space = \space \frac{E}{t}$

$\space = \space \frac{4P}{\pi d^2}$

By putting values, we get:

$\space = \space \frac{4 \space . \space 66700}{\pi \space . \space 0.001^2}$

$\space = \space 8.5 \space . \space 10^{10} \space \frac{W}{m^2}$

The power of a single laser pulse is:

$\space = \space 66.7 \space kW$

The strength of the light wave during the incredibly brief pulse is:

$\space = \space 8.5 \space . \space 10^{10} \space \frac{W}{m^2}$

## Example

Laser light pulses are used during LASIK eye surgery to reshape the cornea by shaving off tissue. A common LASIK laser produces a $193 nm$ laser beam that is $2.0 mm$ in diameter $. 15 ns$  and $1.0 mj$ of visible light are contained in each laser pulse. How powerful is a single laser pulse? What’s the strength of a light wave during the incredibly brief pulse?

First, we have to calculate how powerful is a single laser pulse. The amount of energy released in relation to the amount of time it was released will determine the power. So:

$\space P \space = \space \frac{E}{t}$

By putting the values, we get:

$\space = \space \frac{2 \space . \space 10^-3} {1.5 \space . \space 10 ^-8}$

$\space = \space \frac{1.333 \space . \space 10^-3}{10^-8}$

$\space = \space 1.333 \space . \space 10^5$

$\space = \space 133333.33$

$\space = \space 133333.33\space W$

Now we have to find the strength of the light wave.

So:

$\space I \space = \space \frac{E}{t}$

$\space = \space \frac{4P}{\pi d^2}$

By putting values, we get:

$\space = \space \frac{4 \space . \space 133333.33}{\pi \space . \space 0.002^2}$

$\space = \space 4.24 \space . \space 10^{10} \space \frac{W}{m^2}$

The power of a single laser pulse is:

$\space = \space 133333.33\space W$

The strength of the light wave during the incredibly brief pulse is:

$\space = \space 4.24 \space . \space 10^{10} \space \frac{W}{m^2}$