  Detecting nonclassical properties that do not allow classical interpretation
of photoelectric counting events is one of the crucial themes in quantum
optics. Observation of individual nonclassical effects for a single-mode field,
however, has been so far practically confined to sub-Poissonian statistics and
quadrature squeezing. We show that a photon-added classical (coherent or
thermal) state exhibits generalized nonclassical features in all orders of
creation and annihilation operators, thereby becoming a promising candidate for
studying higher-order nonclassical effects. Our analysis demonstrates
robustness of these effects against nonideal experimental conditions.
