Read a little about dielectric spectroscopy on Wikipedia and you will see that you seem to have some electronic polarisation mechanism in the infrared, with a maximum around 1100nm and a second smaller bump around twice that wavelength (so, half the frequency or energy, for which there could be two explanations).

Is this a metallic sample with Drude modelling employed for the results?

Dear Aryan,

You need to give more information about the sample that generate these spectra. As they come from ellipsometry, you should precise if the measurement was obtained on a bulk sample or on a thin film structure.

In first case, spectra simply display dielectric function of the material that is surprisingly getting more transparent when wavelength decrease.

In second case, they display what is usually called pseudo dielectric function in ellipsometry and it definitely needs structure information to go further in the analysis.