Specific Process Knowledge/Back-end processing/Laser Micromachining Tool/fluence

Fluence definition

The fluence produces by a laser is, by definition, the energy delivered by a laser pulse (Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle E_{pulse}} ) per surface unit (Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} ) and it is given in J/cm2.

The function Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle E_{pulse}} is defined as :

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle E_{pulse} = \frac{\overline{P}}{f}\,}

Where Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \overline{P}} (average power) is measured with the laser sensor power measurement (see manual,section 5.3) and the repetion rate (Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle f} ) is set in the parameter file under " laser frequency".

The fluence is therefore determinated as such :

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle Fluence = \frac{E_{pulse}}{A}\,}

The area (Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} ) can be determinate with the theoretical min spot diameter (1/e2), available here

Fluence results measurement

The results below have been calculated with the theoretical spot size provided by 3D Micromac.

Fluence result for IR wavelength (1064nm, F255mm)	Fluence result for green wavelength (532nm, F255mm)	Fluence result for UV wavelength (355nm, F100mm)

Fluence result for IR wavelength (IPG 1064nm, F255mm). The fluence at 100% and 10kHz must be expected around 25J/cm2