Eye-Safe Wavelength Laser Fluorimeter for Noncontact Monitoring the Ecological Condition of Objects in Natural Environment

Abstract

Presently, a problem of ecological monitoring of natural environment is critical.Laser methods are the most powerful to provide noncontact and remote ecological monitoring of natural environment. Among laser monitoring methods, laser fluorescent ones are of strong interest.Today, there are laser fluorescent devices designed to monitor ecological condition of various objects in natural environment. To produce laser-induced fluorescence excitation, laser fluorescent devices use a variety of radiation sources in the spectral band from 226 to 635 nm.However, to have an advanced laser fluorescent device for noncontact ecological monitoring of natural environment, devices to be created should be multifunctional and use an eye-safe wavelength for fluorescence excitation.A fluorescence excitation wavelength of 355 nm (the third harmonic of a YAG: Nd laser) appears to be promising. This wavelength is eye-safe and can be used to monitor ecological condition of a large number of nature-made objects.The paper conducts a capability analysis of noncontact laser fluorescent monitoring of ecological condition of natural environment using the eye-safe fluorescence excitation wavelength of 355 nm. Describes a laser fluorimeter mock-up and presents experimental results of laser-induced fluorescence spectra of nature-made objects.The experimental studies have shown that the noncontact laser fluorimeter using the eye-safe fluorescence excitation wavelength of 355nm potentially allows us to control the ecological condition of a large number of nature-made objects.The fluorescence intensities in the certain spectral ranges (for example, within the spectral range of ~ 425 – 450 nm) and a spectrum profile of plant fluorescence (in the spectral range of 670 - 750 nm) can be used as the controlled variables.