Yes, it is normal to notice that type of smell during an ablative laser treatment. Ablation means, to remove body tissue through vaporization. During a Halo laser treatment at my practice, we use a cooling fan and suction to limit the burning smell and make the procedure more comfortable for the patient. Even with the fan and suction, it is normal to have a hint of that smell. Hope this helps.
HALO is a hybrid fractional laser with ablation that removes some skin so what you describe can be normal; however, the smoke evacuator should be suctioning all of that smoke and odor up. If it isn't, sometimes the suction needs to be turned higher. You had a wonderful treatment with HALO. You should see your doctor for follow up within a week.