I think it is AI, correct me if I'm wrong. Thanks in advance
This is easily achievable in Photoshop.
- Start with a greyscale image and then go to Image > Mode > Bitmap
- In the pop-up, select Halftone Screen... as the Method (The Output Resolution should be equal to or greater than the Input Resolution)
- Hit OK
- In the next screen select Line from the Shape drop down menu and set the frequency to something low (like less than 10)
- Hit OK
This will create the effect that you are looking for but you probably won't like the result at the first attempt. You will need to experiment with the following parameters until you are happy :
- Output Resolution (Higher values smooth the result)
- Frequency (Lower numbers give thicker lines)
- Angle (changes the angle of the lines)
It will take a bit of experimentation, but it shouldn't take long to get a nice result.
For further effects try different Halftone Screen Shapes.