Infrared neuromodulation (INM) is a safe optical method used to stimulate neuronal populations by locally changing the temperature within the brain tissue. Sleep and neural activity during sleep are highly temperature-dependent. During anesthetized in vivo measurements, the low-frequency components increase compared to vigilance. Therefore, we examined the changes in the frequency bands corresponding to delta and theta waves and sleep spindles during continuous infrared stimulation. The experimental device used for INM was a sharp-tip optrode, that holds an embedded waveguide that transmits infrared light into the cortical tissue. The shaft of the device comprises 12 linearly placed electrodes. These electrodes recorded local field potential activity across cortical layers in acute in vivo measurements performed in 8 rats with 5 repeated infrared stimulations. In this preliminary study, we present the stimulation-related changes in the selected frequency bands considering two channel groups (located close and far from the stimulation location). Our study revealed that delta power increases in supragranular layers of the neocortex during optical modulation, while lower delta power was observed in infragranular layers. Along with the spectral analyses, a multiunit activity-based up/down state detection method was performed on these data. We found that the duration of down-states of the cortical slow waves increased during stimulation, while up-states became shorter. Our future aim in this study is to investigate the temperature dependency of slow waves and to characterize the effect of infrared neuromodulation on state lengths during anesthesia.