Multi-Mode Sample Inspection with Tunable Spectral Filtering

The patent replaces expensive, complex continuous-wave laser systems with simpler, more cost-effective pulsed laser sources. While pulsed lasers have broader spectral linewidths, this trade-off is acceptable given the significant reduction in system complexity and cost, especially when combined with spectral filtering techniques to manage chromatic aberration

The patent changes the operational parameters of the laser source from continuous-wave to pulsed mode, and adjusts the spectral linewidth through filtering. This parameter change allows the use of simpler laser hardware while managing the resulting chromatic dispersion through optical filtering and detector design

The patent introduces spectral filters as intermediary elements between the pulsed laser source and the sample. These filters selectively transmit certain wavelengths while blocking others, effectively narrowing the spectral linewidth reaching the sample and reducing chromatic dispersion without requiring complex aberration-corrected optics

The patent applies spectral filtering to selectively pass only the necessary wavelength range for inspection, rather than attempting to correct all chromatic aberrations across the entire spectrum. This partial action approach achieves sufficient resolution for particle detection while maintaining system simplicity

The patent converts the harmful effect of broad spectral linewidths into a beneficial feature by using the full spectral bandwidth of pulsed lasers to improve signal strength, while managing chromatic aberration through detector design and processing techniques rather than attempting to eliminate it entirely

The patent employs dynamic spectral filtering where the effective bandwidth and wavelength range are adjusted based on the specific inspection requirements. This allows optimization of the balance between signal strength and chromatic aberration for different particle sizes and inspection conditions