  Under very general assumptions of metric theory of spacetime, photons
traveling along null geodesics and photon number conservation, two observable
concepts of cosmic distance, i.e. the angular diameter and the luminosity
distances are related to each other by the so-called distance duality relation
(DDR) $D^L=D^A(1+z)^2$. Observational validation of this relation is quite
important because any evidence of its violation could be a signal of new
physics. In this paper we introduce a new method to test DDR based on strong
gravitational lensing systems and type Ia supernovae under a flat universe. The
method itself is worth attention, because unlike previously proposed
techniques, it does not depend on all other prior assumptions concerning the
details of cosmological model. We tested it using a new compilation of strong
lensing systems and JLA compilation of type Ia supernovae and found no evidence
of DDR violation. For completeness, we also combined it with previous cluster
data and showed its power on constraining DDR. It could become a promising new
probe in the future in light of forthcoming massive strong lensing surveys and
because of expected advances in galaxy cluster modlelling.
