Relativistic Optics and Applications with Ultra-Intense Lasers

The advent of ultrahigh intensity lasers has enabled us to extend the reach of optics into the relativistic regime, where the dynamics of matter is characterized by the relativistic dynamics of electrons in the optical fields. The rectification of the optical fields into a longitudinal field via the Laser Wake Field Acceleration (LWFA) initiated what is now called high field science, in which the relativistic nonlinearity and coherence play central roles. Laser acceleration of electrons and then ions has advanced from a sheer concept into a practical devises and future accelerator hope. We will survey the characteristics of laser acceleration of particles and introduce several of the present applications.  These include applications to radiolysis, fast diagnosis, cancer therapy, X-ray free electron laser seeds, THz radiation sources, and more. There are wider applications of utilization of ultra-intense lasers combining lasers and accelerators. An example is to generate gamma rays by the backscattering of laser off electron beams, whose applications include photonuclear physics such as the nuclear resonance fluorescence (NRF), which can decipher ,without contact, the nuclear isometric content and constituents. Finally, the exploitation of relativistic dynamics and coherence in conscious efforts (what we call relativistic engineering) can lead to an entirely new way of manipulating electrons, photons, and other particles in relativistic regimes that no other method can bring easily, such as in time scales (atto- and zeptoseconds), intensity (toward the Schwinger fields), and frequencies (such as up to gamma rays).