He serves as: a chief scientist supporting the Lasers and Alignment Systems Engineering group; is responsible for platform development for experiments that use the Advanced Radiographic Capability (ARC); is senior scientist for the NIF User Office; and supports external users develop and execute experiments at NIF through the Discovery Science program.

He developed a number of complex experiments, including measurement of direct laser imprint by XUV radiography with an x-ray laser on Nova 2-Beam, in-flight radiography of an imploding capsule, and material strength and in-situ diffraction measurements of highstrain- rate materials on Nova 10-Beam, OMEGA, and at other laser facilities.

In 2019, Kalantar was recognized as a Distinguished Member of the Technical Staff at LLNL.