I found the MIT Tech Review's summary confusing. I didn't understand the article it was based on fully, but the idea seems to be covered in the following paragraph:
Time-space duality represents the analogy between diff raction and dispersion that arises from the mathematical equivalence between the equations describing the diff raction of a beam of light and the one-dimensional temporal propagation of a pulse through a dispersive medium [17,18]. Similar to a spatial lens that imparts a quadratic phase in space, a time-lens can be implemented that produces a quadratic phase shift in time [19{21]. This time-lens can, for example, magnify [22] or compress [23] signals in time and has an equivalent of the lens law. Time-lenses can be created with an electro-optic modulator [18] or via a parametric nonlinear optical process such as four-wave mixing (FWM) with a chirped pump wave [19,20]. In the latter case the signal wave is converted to an idler wave with a linear frequency shift in time (i.e., a quadratic phase in time) [21,22].
I understand this to mean that the passage of time in observed space can be slowed down relative to an observer, rather as happens when observing a body falling into a black hole.
Time-space duality represents the analogy between diff raction and dispersion that arises from the mathematical equivalence between the equations describing the diff raction of a beam of light and the one-dimensional temporal propagation of a pulse through a dispersive medium [17,18]. Similar to a spatial lens that imparts a quadratic phase in space, a time-lens can be implemented that produces a quadratic phase shift in time [19{21]. This time-lens can, for example, magnify [22] or compress [23] signals in time and has an equivalent of the lens law. Time-lenses can be created with an electro-optic modulator [18] or via a parametric nonlinear optical process such as four-wave mixing (FWM) with a chirped pump wave [19,20]. In the latter case the signal wave is converted to an idler wave with a linear frequency shift in time (i.e., a quadratic phase in time) [21,22].
I understand this to mean that the passage of time in observed space can be slowed down relative to an observer, rather as happens when observing a body falling into a black hole.