The present invention discloses an optical device comprising a container enclosing an insulating liquid (A) and an electrically susceptible liquid (B), the insulating liquid (A) and the electrically susceptible liquid (B) being immiscible and being in contact with each other via an interface (14), at least one of the liquids (A; B) being at least partially placed in a light path through the container. The optical device further comprises heating means (2, 12, 20) that preferably are responsive to a temperature sensor (30) for heating the insulating liquid (A) and the electrically susceptible liquid (B). Consequently, an optical device is obtained in which the influence of the temperature dependence of the physical properties of the insulating liquid (A) and the electrically susceptible liquid (B) on the behaviour of the optical device is reduced, thus yielding an optical device with improved optical characteristics at low temperatures.