Raychaudhuri has worked in diverse areas within particle physics encompassing quantum chromodynamics, grand unified theories, classical solutions, left-right symmetric models, FCNC, supersymmetry, neutrino physics, extra dimensions, etc. He made pioneering contributions in CP-violation in supersymmetric models, the possibility of parity restoration at relatively low energies, neutrino masses and mixing in supersymmetric and other models, long baseline neutrino experiments, besides making a brief but important foray in the foundations of quantum mechanics. He holds a reputation of a charismatic teacher among his students.