This is called the Oblique Cut or Roll Cut. This technique is useful when you want a larger surface area for glazing, for reducing cooking time, or simply for aesthetic reasons.
You hold the carrots with your anchor hand and the knife at a 45 degree angle.
Cut, roll the carrot a quarter turn toward you. Cut, roll, cut, roll.
Carrots (and other cylindrical vegetables like zucchini, parsnips) cut this way will give you more surface area.
Try it with a late harvest sauté of zucchini, corn and red bell peppers.
Use this cut for carrots or parsnips going into daube or stew or Japanese nimono.
Glaze the carrots with duck fat, Chinese Five Spice, a splash of orange juice and sprinkle of sugar.