Method for laser functional trimming of films and devices

A method for modifying with laser output a measurable operational parameter of an activated electronic device while preventing a spurious optoelectric response in the device, the device including target material and nontarget material positioned within optical proximity to the target material, the laser output including a laser pulse having a spatial distribution of energy that impinges the target material and exposes the nontarget material to extraneous laser output, the target material having ablation sensitivity to laser output in a first wavelength range and the nontarget material having optoelectric sensitivity to wavelengths in a second wavelength range that forms a subset of the first wavelength range such that exposure to a wavelength within the second wavelength range causes spurious optoelectric effects in the nontarget material that transiently obscure for a time interval concurrent with and following the laser pulse a true value of the measurable operational parameter of the device, comprising:

• determining a third wavelength range of laser output for which the nontarget material has substantial optoelectric insensitivity, the third wavelength range excluding the second wavelength range;
• activating the device;
• generating a laser pulse at a selected wavelength that falls within an overlapping region of the first and third wavelength ranges;
• impinging the target material with the laser pulse having sufficient power to ablate a portion of the target material;
• and
• measuring within the time interval a true value of the operational parameter of the device.