Early research into the use of lasers included the development of techniques for the manipulation of structures within a living cell. What Bern terms "Laser scissors" use short pulses of high irradiance to create targeted effects.
Optoporation has been used to create tiny openings into the interior of a cell, enabling the genetic manipulation of cells by the insertion and deletion of genes, and the extraction and examination of
microplasma from within the cell.
Laser ablation can be used to destroy or inactivate cells. Lasers can also be used to optically trap cellular structures. "
Laser tweezers" use continuous, low-irradiance beams that pass through substances without causing damage. The refraction of a pair of symmetric laser light rays within a beam can be modified and cause the target to respond to the change in momentum of the light rays. More advanced research has included optical techniques such as Multiphoton microscopy, Second-harmonic imaging microscopy, Photoacoustic tomography, nonlinear Raman spectroscopy, and diffuse optical spectroscopy.
Photoacoustic tomography enables researchers to create three-dimensional images of deep tissue. A laser must be carefully tuned to excite specific bonds so that they "rattle", creating noise that can be detected and mapped by passive acoustic systems. SFDI can detect subsurface damage to bruised tissues such as the skin or brain by examining hemoglobin levels. ==Applications==